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A framework for evaluating the safety benefits of intelligent transportation systems Vahidi, Homayoun 2002

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A F R A M E W O R K FOR E V A L U A T I N G THE SAFETY BENEFITS OF INTELLIGENT TRANSPORTATION SYSTEMS by H O M A Y O U N VAHIDI Dipl. Tech. British Columbia Institute of Technology, 1987 B.Eng., Ryerson Polytechnic Institute, 1992 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF M A S T E R OF APPLIED SCIENCE in THE F A C U L T Y OF G R A D U A T E STUDIES (Department of Civil Engineering; Transportation) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH C O L U M B I A April 2002 © Homayoun Vahidi, 2002 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of <g-«\hv— ^-*-\t^vA.-&^-^.tX('s\ The University of British Columbia Vancouver, Canada ABSTRACT The benefits of ITS are indirectly represented by the annual world market for ITS, which according to ITS Canada will be C D N $90 billion by 2011. Improved safety is often cited as being the top goal of implementing ITS, followed by others relating to efficiency, economic productivity, and the environment. However, despite the magnitude of these investments and their underlying goal to improve transportation safety, and despite the inherent recognition of the safety improvement potential of ITS by transportation professionals, there is a deficiency in the quantity and quality of reported ITS safety benefits. Much of the existing evaluations and reported benefits to date suffer from the lack of an evaluation framework and inconsistent terminology used to attribute benefits to ITS application areas. In light of these issues, and the ongoing need in the ITS community to better demonstrate the safety benefits of ITS, a framework has been developed for evaluating the safety benefits of ITS. This framework is unique in that it uses the ITS application areas defined by the market packages in the Canadian ITS Architecture and categorizes and correlates them against a distinct set of metrics defined to measure the safety benefits of ITS. Furthermore, the metrics are correlated with each other to capture the "cause" and "effect" flow of benefits and how each market packages contributes to the fundamental goal of reducing the number and severity of crashes. The need for this approach has been illustrated through a case study that demonstrates the potential disparity in benefit estimates when no framework is used. This framework will benefit future evaluations of ITS safety benefits by providing a structure for undertaking evaluations and reporting of benefits, while addressing the terminology issue through an interface with the Canadian ITS Architecture. This framework forms the basis of i i developing similar frameworks related to measuring benefits associated with other ITS goals. Each of these individual frameworks could be linked together (via their common "cause" and "effect" metrics to provide an overall framework for evaluating all ITS benefits. This overall framework could be integrated with the Canadian ITS Architecture documentation and training programs to ensure that the evaluation of ITS benefits becomes an integral part of ITS planning and design. iii T A B L E O F C O N T E N T S ABSTRACT ii TABLE OF CONTENTS iv LIST OF TABLES vi LIST OF FIGURES viii ACKNOWLEDGEMENTS ix GLOSSARY OF TERMS x 1 INTRODUCTION 1 l . l BACKGROUND ON THE BENEFITS OF ITS 2 1.2 ITS & SAFETY 5 1.3 PURPOSE AND METHODOLOGY 6 2 LITERATURE REVIEW 8 2.1 FUNCTIONAL AREAS OF ITS 8 2.1.1 Early References to ITS Application Areas 8 2.1.2 US Architecture for ITS 9 2.1.3 Canadian Architecture for ITS 12 2.2 CURRENT ITS EVALUATION PRACTICES 16 2.2.1 COMPASS (Toronto, Ontario) 17 2.2.2 Trans Canada Highway Monitoring & Evaluation Program 18 2.2.3 ITS Evaluations in Texas 19 2.2.4 Washington State 21 2.2.5 US ITS Architecture ITS Performance & Benefits Study 22 2.2.6 USDoT- ITS Benefits Database 26 2.2.7 US DoT - Estimating Potential ITS Safety Benefits 28 3 SUMMARY OF BENEFITS REPORTED TO DATE 32 3.1 METROPOLITAN ITS INFRASTRUCTURE 33 3.1.1 Arterial Management Systems 33 3.1.2 Freeway Management Systems 36 3.1.3 Incident Management Systems 39 3.1.4 Emergency Management 41 3.1.5 Regional Multi-modal Traveller Information 41 3.1.6 Transit Management 42 3.2 ITS INFRASTRUCTURE IN RURA L AREAS 42 3.2.1 Emergency Services 45 3.3 ITS FOR COMMERCIAL VEHICLE OPERATIONS ( C V O ) 45 3.4 SUMMARY OF BENEFITS REFERENCED 47 4 ISSUES 50 4.1 TERMINOLOGY 50 4.2 GAPS IN KNOWLEDGE 51 iv 4.2.1 Extent of Deployment 51 4.2.2 Lack of Evaluation Data 52 4.2.3 Lack of a Framework 53 4.3 P R O B L E M / N E E D S T A T E M E N T S U M M A R Y 5 6 5 PROPOSED EVALUATION FRAMEWORK 58 5.1 M A R K E T P A C K A G E S IN T H E C A N A D I A N I T S A R C H I T E C T U R E 5 9 5.2 IDENTIFYING T H E M E T R I C S OF T H E F R A M E W O R K 61 5.3 M A P P I N G OF T H E M A R K E T P A C K A G E S TO T H E M E T R I C S 6 4 5.5.7 Advanced Traveller Information Systems (ATIS) 64 5.3.2 Advanced Traffic Management Systems 66 5.3.3 Advanced Public Transportation Systems 69 5.3.4 Commercial Vehicle Operations 71 5.3.5 Emergency Management 73 5.3.6 Advanced Vehicle Safety Systems 74 5.3.7 Archived Data 75 5.4 F R A M E W O R K S U M M A R Y & A P P L I C A T I O N G U I D E L I N E S 7 6 5.5 F R A M E W O R K BEN EFI TS 82 6 CASE STUDY 85 6.1 P R O P E R S A F E T Y E V A L U A T I O N S 85 6.1.1 Confounding Factors 86 6.1.2 Techniques to Address Confounding Factors 88 6.2 C A S E S T U D Y P R O J E C T ( R E S C U T O R O N T O , O N T A R I O ) 9 0 6.2.1 Available Crash and Traffic Volume Data 91 6.2.2 "Best Possible" Safety Evaluation 97 6.2.3 Simple Before and After Comparison of Crash Frequencies 98 6.2.4 Simple Before and After Comparison of Crash Rates 100 6.2.5 Simple Before and After with a Comparison Group 103 6.3 S U M M A R Y OF A N A L Y S I S R E S U L T S 109 6.3.1 Data Deficiencies 109 6.3.2 Impacts of Methodology UO 6.4 F R A M E W O R K A P P L I C A T I O N 112 6.4.1 Framework Application & Benefits During Project Planning 112 6.4.2 Framework Application & Benefits During Project Design 114 6.4.3 Framework Application & Benefits During Evaluation and Reporting 115 7 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS 116 7.1 P O T E N T I A L FOR I T S TO I M P R O V E S A F E T Y 116 7.2 W O R K D O N E TO D A T E & A S S O C I A T E D ISSUES 116 7.3 D E V E L O P E D E V A L U A T I O N F R A M E W O R K A N D ITS BENEFITS 117 7.4 F U R T H E R R E S E A R C H 119 REFERENCES 121 APPENDIX A - Market Packages in the Canadian ITS Architecture 124 v LIST OF T A B L E S Table 2.1 - User Services in the US National ITS Architecture 11 Table 2.2 - Summary of User Service Bundles in the Canadian and US Architectures 13 Table 2.3 - User Services in the Canadian ITS Architecture 15 Table 2.4 - COMPASS Objectives and MOEs 18 Table 2.5 - British Columbia's Trans Canada Highway Objectives and MOEs 19 Table 2.6 - MOEs Used in the Evaluation of TrasGuide 20 Table 2.7 - ITS Goals and Performance Evaluation Metrics 24 Table 2.8 - ITS Countermeasures, Crash Reduction Factors, & Confidence Levels 30 Table 2.9 - Estimated Percent Crash Reduction Factors for Injury Crashes in the US 31 Table 2.10 - Estimated Percent Crash Reduction Factors for Fatal Crashes in the US 31 Table 3.1 - Reported Safety Benefits of Ramp Metering 37 Table 3.2 - Summary of Rural Crash Causes Versus Percent Vehicles 44 Table 3.3 - Number of References for Metropolitan ITS Infrastructure Safety Benefits 47 Table 3.4 - Number of References for Rural ITS Infrastructure Safety Benefits 48 Table 3.5 - Number of References for Metropolitan ITS Infrastructure Safety Benefits 49 Table 4.1 - Summary of Safety Related Benefits Data in the FHWA's Database 53 Table 4.2 - Pros and Cons of Existing Evaluation Methodologies 55 Table 5.1 - New or Modified Market Packages in the Canadian ITS Architecture 60 Table 5.2 - Cause & Effect Metrics 61 Table 5.3 - ATIS Market Packages 65 Table 5.4 - A T M S : Monitoring and Safety Market Packages 67 Table 5.5 - A T M S : General Traffic Management Market Packages 68 Table 5.6 - A T M S : Information Warning Market Packages 69 v i Table 5.7 - ATMS: Enforcement Market Packages 69 Table 5.8 - APTS Market Packages , 70 Table 5.9 - CVO: Regulatory Market Packages in the Canadian ITS Architecture 72 Table 5.10 - CVO: Vehicle/Freight Market Packages 73 Table 5.11 - Emergency Management Market Packages 73 Table 5.12 - AVSS: Monitoring System Market Packages 74 Table 5.13 - AVSS: Warning System Market Packages 75 Table 5.14 - AVSS: Automated System Market Packages 75 Table 5.15A - Mapping Market Packages to Metrics 77 Table 5.15B - Mapping Market Packages to Metrics 78 Table 5.16 - Summary of Framework Categories to Metrics 79 Table 5.17 - Potential Data Relationships for an ITS Safety Benefits Database 80 Table 6.1 - Crash Database Deficiencies and Clean-up Procedures 93 Table 6.2 - Comparison of Total Crash Frequencies 99 Table 6.3 - Comparison of Rear-End Crash Frequencies 99 Table 6.4 - Comparison of Severe Crash Frequencies 99 Table 6.5 - Comparison of Total Crash Rates 101 Table 6.6 - Comparison of Rear-End Crash Rates 101 Table 6.7 - Comparison of Severe Crash Rates 102 Table 6.8 - Treatment Effect of Total Crashes 105 Table 6.9 - Treatment Effect of Rear End Only Crashes 106 Table 6.10 - Treatment Effect of Severe Only Crashes 107 Table 6.11 - Market Packages Incorporated in R E S C U 113 vii LIST O F FIGURES Figure 1.1 - ITS Beneficiaries & Application Areas 2 Figure 2.1 - Relationship Between System Architecture and ITS Benefits 22 Figure 2.2 - Benefit - Flow Diagram: Market Package to Metrics 25 Figure 2.3 - Benefit Flow Diagram: Metrics to Goals 26 Figure 3.1 - FHWA's ITS Benefits Taxonomy 33. Figure 5.1 - Framework Development Process 59 Figure 5.2 - Cause & Effect Flow of Metrics 63 Figure 6.1 - Example of R T M Effect 88 Figure 6.2 - Gardiner Expressway Context Map 90 Figure 6.3 - Gardiner Expressway Crash Frequency 94 Figure 6.4 - Don Valley Parkway Crash Frequency 94 Figure 6.5 - Comparative Plot of Crash Frequencies 95 Figure 6.6 - Gardiner Expressway Average AATDs ...96 Figure 6.7 - Percent Reduction in Crash Frequency 100 Figure 6.8 - Percent Reduction in Crash Frequency 102 Figure 6.9 - Percent Changes in Crash Rates Using a Comparison Group 108 Figure 6.10 Variations in Crash Reduction Estimates Due to Methodology I l l viii A C K N O W L E D G E M E N T S In submitting this thesis, I would like.to thank Dr. Sayed and Dr. Navin for helping me stay on track despite the distractions of my career. Similarly, I would like to thank IBI Group, and especially Andy McNally for giving me the freedom I needed to stay on track and complete this effort. Finally, I am grateful to the continued support and patience of my family during the course of this work. ix G L O S S A R Y OF T E R M S APTS Advanced Public Transportation Systems ARTS Advanced Rural Transportation Systems A T M S Advanced Traffic Management Systems ATRWS Automatic Truck Rollover Warning Systems ATIS Advanced Traveller Information System A V S S Automatic Vehicle Safety Systems B C MoT British Columbia Ministry of Transportation c v o Commercial Vehicle Operations DTWS Downhill Truck Warning System EB Empirical Bayes F H W A Federal Highway Administration ISTEA Intermodal Surface Transportation Efficiency Act ITS Intelligent Transportation Systems IVHS Intelligent Vehicle Highway Systems JPO Joint Program Office (FHWA) M O E Measure of Effectiveness M T O Ministry of Transportation of Ontario OR Odds Ratio R T M Regression to the Mean SCATS Sydney Coordinated Adaptive Traffic System TTI Texas Transportation Institute TxDoT Texas Department of Transportation US DoT . United States Department of Transportation WLM Weigh in Motion 1 I N T R O D U C T I O N Intelligent Transportation Systems (ITS) encompass the application of advanced information, computer, and communications technologies to improve the surface transportation system. According to ITS Canada (2002), ITS is "an emerging global phenomenon'''' involving "a broad range of diverse technologies applied to transportation to save lives, money and time." ITS contribute to improving the surface transportation system by increasing mobility, improving service levels and safety, while helping to reduce energy consumption, and impacts to the environment. ITS enhances the ability of transportation systems and services to move people, goods, and information efficiently and safely. While technology applications have been part of our transportation systems for a long time, advances in computing and communication technologies over the last two decades have made it more feasible to deploy systems that make for a more "dynamic" transportation system, one that can better serve the needs of users and operators by monitoring, managing, and responding to prevailing and predicted conditions. Historically, the deployment of traffic actuated signals can be considered as a form of ITS (even though the term did not exist then), representing an application that helps optimize the timing of a traffic control signal by allocating green time based on directional demands. Today, ITS applications are much broader and far more complex; for example, corridor traffic management systems incorporating incident detection and traveller information can help optimize flows over a wide area by diverting traffic to routes with available capacity during incident conditions. 1 These advances are permitting the providers and operators of the transportation system to shift their focus from building new infrastructure (which is becoming increasingly difficult efficient and safe) and capable of managing growing demands. 1.1 Background on the Benefits of ITS The annual world market for ITS was estimated to be $24 billion in 2001, and is estimated to be $90 billion by 2011 (ITS Canada, 2001). The scale of these expenditures suggests that the magnitude of ITS benefits exceed costs significantly. ITS benefits are experienced by various beneficiary groups, such as general public users of the transportation system, commercial users and fleet operators, as well as by the actual owners, operators, and regulators of the transportation system. Furthermore, these beneficiaries can experience ITS benefits in urban or rural settings, or within their vehicles. Figure 1.1 illustrates this concept schematically, and facilitates the overview discussion of ITS benefits presented in this section. due to lacking financial and manpower resources) to making existing systems smarter (more BENEFICIARIES APPLICATION AREAS General Public Users Commercial / Fleet Users Infrastructure Owners, Operators, & Regulators Urban Rural n-Vehiele Figure 1.1 - ITS Beneficiaries & Application Areas 2 Traffic management systems benefit general public users and commercial/fleet users by improving traffic flows and reducing delays and congestion - which all improve safety. These benefits are derived through applications that monitor traffic conditions in real time and provide adaptive responses - such as through ramp meters that control the entry of vehicles onto a highway, or by responding and clearing incidents more quickly. These benefits also extend to the owners and operators of transportation facilities, whereby the available capacity of existing infrastructure is optimized - resulting in possible deferrals associated with infrastructure expenditures for the purposes of increasing capacity. These types of traffic management applications also form the basis for the integration of other applications in the areas of emergency management and enforcement systems. For example, ITS applications in the areas of emergency vehicle dispatching and emergency signal pre-emption build on top of the traffic monitoring technologies of a traffic management system (which help detect incidents quicker), thus resulting in shorter response times to incidents which in turn leads to less disruption to traffic and improved safety. Similarly, the application of monitoring technologies can extend to speed and red-light violation enforcement systems; making it more cost effective to provide enforcement over wider geographical areas and in turn making the roads safer for travel. ITS applications to public transportation systems benefit both the general public and the owners and operators of the transit systems. Here, general users benefit by receiving enhanced transit services that are more accessible and reliable. ITS helps derive these benefits through applications such as transit priority for buses (which improve travel time and trip time reliability), and electronic payment systems (which make payments more convenient and reduce transaction times). Similarly, operators benefit by being able to 3 manage their fleets and services better; ITS helps derive these benefits through the integration of fleet based communication, automatic passenger counting, vehicle location monitoring, and vehicle control technologies - all of which help to improve the overall planning, scheduling, and operations of transit systems (US DoT, 2000). Combined, ITS applications to traffic management and public transportation support advanced applications in the area of traveller information. Using various sources of monitoring real-time traffic, transit and weather conditions, users of the transportation system benefit by being able to make more informed decisions about their time, mode, and route of travel. In urban areas, the availability of this type of information helps reduce person delays by informing travellers of congestion and incident hotspots. In rural areas, accessibility to this type of information helps users avoid hazardous conditions. ITS applications to commercial vehicle operations benefit carriers and feet operators as well as public agency regulators. In the areas of safety assurance, credentials administration, and electronic screening, operating expenses can be reduced through increased efficiency, while assisting in ensuring the safety of motor carriers on the roadways. For example, improved safety information exchange helps improving safety by providing inspectors with better access to safety information, so the number of unsafe commercial drivers and vehicles removed from the roadways can be increased. These benefits are enhanced with electronic screening applications that allow the safety record, credentials, and other pertinent information of commercial vehicles to be scanned at free-flow speeds. Electronic screening of commercial vehicles can reduce congestion at inspection stations, improve travel time for commercial vehicles, and help operating companies and regulating agencies reduce costs. 4 A l l o w i n g safe and legal carriers to bypass weight and safety inspect ion stations without stopping can reduce congest ion at the faci l i t ies (Mitretek Systems Inc. , 2001). S i m i l a r to the p u b l i c transportation system applicat ions, c o m m e r c i a l v e h i c l e applications can also benefit from fleet management systems that can help carriers track vehic les and cargo, i m p r o v i n g their internal operations and p r o v i d i n g support for enhancing coordinat ion w i t h regulat ing agencies. I T S appl icat ions also extend inside the vehic le , and hence so do the benefits. M o s t benefits are either convenience oriented or safety orient. F o r example, i n v e h i c l e nav igat ion systems that use g loba l p o s i t i o n i n g technologies to relate vehic le p o s i t i o n to a map d i s p l a y i n the v e h i c l e increases the dr iver ' s convenience. M o r e important ly however , applicat ions i n the areas o f v i s i o n enhancement m a y i m p r o v e safety for d r i v i n g condi t ions i n v o l v i n g reduced sight distance due to night d r i v i n g , inadequate l ight ing , fog, dr i f t ing snow, or other inclement weather condit ions affecting v i s i b i l i t y ( M i t r e t e k Systems Inc., 2001). Safety benefits can also be der ived from c o l l i s i o n avoidance w a r n i n g systems that can m o n i t o r the vehicles ( in real t ime) relative to surrounding vehic les or traction to the ground and p r o v i d i n g warnings or temporary contro l o f the vehic le w h e n a potential for a crash is detected. 1.2 ITS & Safety M a n y o f the potential benefits o f the different I T S applications areas discussed above relate to safety. A l t h o u g h safety is often l isted as one o f the k e y benefits that c a n be real ized from I T S , research and literature support ing the safety benefit c l a i m s is l i m i t e d and fragmented, and not a lways rel iable or conclus ive . 5 On one hand, the lack of a consistent terminology and a common language for discussing ITS has affected the credibility of available research and its reported benefits. For example Shank (ITS Quarterly, 1997) attributes the benefits of a Dynamic Truck Speed Warning System in Colorado to Advanced Traveller Information Systems (ATIS), while Jernigan (1998) attributes benefits of the same project to Advanced Traffic Management Systems (ATMS). On the other hand, the absence of a reliable evaluation framework has undermined the current estimates of ITS safety benefits, either as a result of the way evaluations are carried out, or as a result of the manner in which estimated safety benefit results are reported. Specifically, the lack of a framework has resulted in evaluation studies incorporating different methodologies, metrics, data types, and evaluation time frames to evaluate similar ITS projects. This has resulted in a disparity of benefit estimates that do not consistently account for unrelated effects, that are not always statistically reliable or conclusive, and that cannot be aggregated to provide overall safety benefit estimates. Finally, much of the evaluations are based on simple before and after comparisons of crash data, and do not take into account the effect of confounding factors such as time trends and regression to the mean biases. 1.3 Purpose and Methodology The purpose of this thesis is to address some of these issues by developing a structured framework for evaluating the safety benefits of ITS. The methodology for developing this framework involves the following major steps: 1. Review of available literature to document current evaluation practices and reported safety benefits to date. 6 2. Identification of issues relating to the deficiencies in existing safety evaluation practices. 3. Development of an ITS safety evaluation framework that addresses the key issues identified. 4. Undertaking of a case study to demonstrate the need for, and benefits of, the developed framework. The literature review carried out for this research has been for three separate but related purposes. These are identified below: • Chapter 2 of this thesis presents a review of literature associated with the current terminologies associated with classifying ITS application areas. • Chapter 2 of this thesis also presents a review of the current practices associated with evaluation ITS safety benefits • Chapter 3 of this thesis provides a comprehensive review of ITS safety benefits reported to date. A l l three components of the literature review form the basis of identifying issues associated with ITS safety evaluations. 7 2 LITERATURE REVIEW The purpose of this chapter is to present a summary of current technical literature on ITS application areas and safety related evaluation practices. Specifically, the evolution of terminology associated with the various application areas is presented, followed by a review of current state-of-the-art safety evaluation practices in Canada and the US. 2.1 Functional Areas of ITS The definition and supporting descriptions of ITS application areas have been evolving in tandem with the technologies that make them possible. In North America, during the late 1980s, these application were not called ITS, but they were referred to as Intelligent Vehicle Highway Systems (IVHS). As the application areas of ITS rapidly expanded beyond "vehicles" and "highways" to include transit, commercial vehicle, and payment systems etc, the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 resulted in the creation of the US federal government's Intelligent Transportation Systems program - out of which the term ITS was born. 2.1.1 Early References to ITS Application Areas Early references to the main application areas of ITS have been in terms of the following: • Advanced Traffic Management Systems (ATMS): involve monitoring of traffic conditions for the purposes of managing traffic and incidents, as well as for enforcement. 8 • Advanced Traveller Information Systems (ATIS): involve the provision of traffic and weather information to users of the transportation system through various media such as radio, television, internet, dynamic message signs, as well as to in-vehicle devices. • Advanced Public Transportation Systems (APTS): involve improved transit management through monitoring systems, electronic payment systems, as well as passenger security systems. • Commercial Vehicle Operations (CVO): involve systems that improve safety assurance procedures, credential administration, and carrier operations. • Advanced Rural Transportation Systems (ARTS): involve the adaptation of ITS applications to the rural environment. • In-vehicle Systems: involve systems that improve vehicle performance and assist the driver in operating the vehicle. Earlier references to ITS benefits have typically been in terms of the above major application areas. However, due to the broad nature of these categories, and the areas of overlap among them, correlation of benefits data to these categories has been at a high and aggregate level, limiting their use and reliability. 2.1.2 US Architecture for ITS The development of US National Architecture began 1993 under the sponsorship of the US DoT, and was completed in June of 1996. It was developed to provide a common structure for the design of ITS, by defining the various ITS functions that can be performed, the components or subsystems that can perform them, where these functions reside (e.g., 9 roadside, traffic management centre, or in-vehicle), the interfaces and information flows between subsystems, and the supporting communications requirements for the information flows (Transport Canada, 2000). The U.S. National Architecture resulted in the completion of a set of 18 documents that provide a technical and philosophical foundation for nation-wide ITS deployments. The development of the Architecture also generated information on the potential benefits achievable through integration of various components of the ITS infrastructure (Transport Canada, 2000). The architecture defines an overall framework and language that describes all of the services that ITS can provide for, and the integrated subsystems that can provide them. Although the objectives of this effort were to provide a framework for the definition of appropriate standards, to provide the basis for integration among subsystems; and, to insure a high degree of flexibility in user choice (US DoT, 1999), the resulting product has helped establish a common language for ITS services. Specifically, the US National ITS Architecture is comprised of a series of 31 "User Services" grouped into seven functional bundles. The user services concept was developed to represent what the system will do from the perspective of the user. Table 2.1 presents the 31 user services which formed the basis for the US National ITS Architecture development effort. These user services were jointly defined by a collaborative process involving US DoT and ITS America with significant stakeholder input (US DoT, 1999). 10 B u n d l e ' User Service Travel & Transportation Management Pre-trip Travel Information En-route Driver Information Route Guidance Ride Matching And Reservation Traveller Services Information Traffic Control Incident Management Travel Demand Management Emissions Testing And Mitigation Highway-rail Intersection Public Transportation Operations Public Transportation Management En-route Transit Information Personalized Public Transit Public Travel Security Electronic Payment Electronic Payment Services Commercial Vehicle Operations Commercial Vehicle Electronic Clearance Automated Roadside Safety Inspection On-board Safety Monitoring Commercial Vehicle Administrative Processes Hazardous Material Incident Response Commercial Fleet Management Emergency Management Emergency Notification And Personal Security Emergency Vehicle Management Advanced Vehicle Control & Safety Systems Longitudinal Collision Avoidance Lateral Collision Avoidance Intersection Collision Avoidance Vision Enhancement For Crash Avoidance Safety Readiness Pre-crash Restraint Deployment Automated Vehicle Operation Information Management Archived Data Function Table 2.1 - User Services in the US National ITS Architecture 11 2.1.3 Canadian Architecture for ITS The development of the Canadian ITS Architecture was initiated in August 1999, under the guidance of a steering committee of public and private sector representatives from the Canadian transportation industry (Transport Canada, 2000). Based on review and analysis of international state-of-the-art ITS architecture and standards development activities, the Canadian ITS architecture development process determined that due to the similarities between Canada and the United States, as well as their close proximity and connectivity of the transportation systems, it would be appropriate to adapt the US National ITS Architecture into a Canadian ITS Architecture. In general, the Canadian effort subsumes all of the US National ITS Architecture work and extends and modifies it to provide new services and areas of coverage and to reflect differences between the nations and the existence of new and different stakeholders (Transport Canada, 2000). On this basis, the US National ITS Architecture was adapted to account for requirements important to or unique to Canada, such as: • Ability to integrate with existing legacy systems; • Incorporation of intermodal operations for freight and passenger transportation between highway, rail, air and marine; • Focus on four areas of activity; namely urban, rural, inter-city corridors, and international corridors; • Importance of system safety and human factors; 12 • Efficient utilization of available communications spectrum; • Rapidly expanding role of the Internet; • Bi-lingual language requirements; • Large rural area; • Harsh weather conditions; and • Metric system. The User Services of the Canadian ITS Architecture are organized into 8 User Service Bundles as opposed to the 7 Bundles in the US National ITS Architecture. The major difference being the Travel and Traffic Management User Service Bundle of the US Architecture has been separated into two separate Bundles: Travel Information Services and Traffic Management Services. Table 2.2 illustrates the mapping of User Service Bundles between the Canadian and US Architectures. (Transport Canada, 2000) Canadian ITS Architecture US National IIS Architecture 1. Traveller Information Services 1. Travel And Traffic Management 2. Traffic Management Services 1. Travel And Traffic Management 3. Public Transport Services 2. Public Transportation Management 4. Electronic Payment Services 3. Electronic Payment 5. Commercial Vehicle Operations 4. Commercial Vehicle Operations 6. Emergency Management Services . 5. Emergency Management 7. Vehicle Safety and Control Systems 6. Advanced Vehicle Safety Systems 8. Information Warehousing Services 7. Information Management Table 2.2 - Summary of User Service Bundles in the Canadian and US Architectures 13 Furthermore, the Canadian ITS Architecture includes 35 User Services. Of these 35 User Services, 6 User Services were developed specifically for the Canadian ITS Architecture, including (Transport Canada, 2000): • Operations and Maintenance - provides government agencies, as well as contractors with the resources to manage the operations and maintenance of vehicle fleet and equipment assets, and monitor and manage traffic flow around work zone areas. • Automated Dynamic Warning and Enforcement - provides systems which warn vehicles or motorists of imminent danger, and provide electronic enforcement of traffic control and regulations. • Non-Vehicular Road User Safety - provides warning systems primarily focused on pedestrian and bicyclist safety. • Intermodal Freight Management - provides systems which will monitor the status of freight in-transit, and at freight terminals. • Disaster Response and Management - co-ordinates disaster response strategies from a virtual control centre, and disseminates information to agencies and individuals on traffic conditions, diversion routes etc. • Weather and Environmental Data Management - provides system wide gathering, fusion, and dissemination of information on roadway weather conditions and forecasts. The remaining 29 User Services are based on the 31 User Services subsumed from the US National Architecture. A number of the US User Services were either combined into single 14 User Services, or divided into separate User Services. Table 2.3 lists the User Services in the Canadian ITS Architectures. Bundle User Service Traveller Information Services Traveller Information Route Guidance & Navigation Ride Matching and Reservation Traveller Services And Reservations Traffic Management Services Traffic Control Incident Management Travel Demand Management Environmental Conditions Monitoring Operations and Maintenance Automated Dynamic Warning and Enforcement Non-Vehicular Road User Safety Multi-modal Junction Safety and Control Public Transport Services Public Transport Management En-route Transit Information Demand Responsive Transit Public Travel Security Electronic Payment Services Electronic Payment Services Commercial Vehicle Operations Commercial Vehicle Electronic Clearance Automated Roadside Safety Inspection On-Board Safety Monitoring Commercial Vehicle Administrative Processes Intermodal Freight Management Commercial Fleet Management Emergency Management Services Emergency Notification and Personal Security Hazardous Material Planning and Incident Response Disaster Response and Management Emergency Vehicle Management Vehicle Safety and Control Systems Vehicle-based Collision Avoidance Infrastructure-based Collision Avoidance Sensor-based Driving Safety Enhancement Safety Readiness Pre-Collision Restraint Deployment Automated Vehicle Operation Information Warehousing Information Warehousing Services Weather and Environmental Data Management Archived Data Management Table 2.3 - User Services in the Canadian ITS Architecture 15 Like the US National ITS Architecture, the Canadian ITS Architecture provides a unified framework and language to guide the coordinated deployment of ITS programs within the public and private sectors. It offers a starting point from which stakeholders can work together to achieve compatibility among ITS elements to ensure unified ITS deployment for a given region. The Architecture describes interaction among physical components of the transportation systems including travellers, vehicles, wayside devices, and control centres. It also describes the information and communications system requirements, how data should be shared and used, and the standards required to facilitate information sharing. Overall, the Canadian ITS Architecture defines the functionality of ITS components and the information flows among ITS elements to achieve total system goals (Transport Canada, 2000). 2.2 Current ITS Evaluation Practices A review of current practices and research in the area of evaluating the safety benefits of ITS was also undertaken as part of this literature review. The focus of this review is not on the actual ITS benefits data (which is the subject of Chapter 3), but rather on North American evaluation methods and practices for "attributing" safety benefits to ITS. In this regard, this section provides two Canadian examples whereby the method of evaluation associated with two ITS related projects (one in Toronto, Ontario, and the other in Vancouver, British Columbia) are described. Also, four US examples are provided, whereby the national and state level methods of ITS evaluation or methods of attributing safety benefits to ITS are presented. 16 2.2.1 C O M P A S S (Toronto, Ontario) COMPASS is the name of a freeway traffic management system that the Ministry of Transportation of Ontario (MTO) implemented along Highway 401, in Toronto, in 1991. The system was implemented to respond to traffic congestion problems along one of North America's busiest highways, by facilitating the prompt detection and removal of freeway incidents and vehicle breakdowns, while providing accurate and timely incident and delay information to motorists (MTO, 2001). In 1994, MTO initiated an evaluation of the COMPASS system for the following purposes (MTO, 1994): 1. to evaluate the effectiveness of the initial phase of the COMPASS system; 2. to identify areas of further improvements; 3. to provide a framework for the ongoing assessment of system performance; 4. to compile a database of system performance parameters for future reference and comparison. Although project specific, this study represents one of the first ITS evaluations undertaken in Canada. The framework used the project's originally defined objectives to establish a series of Measures of Effectiveness (MOEs). These objectives and MOEs are summarized in Table 2.4 (MTO, 1994). 17 Objectives MOEs • Reduction of vehicular delay and crash risk due to non-recurring congestion through the rapid detection, response, and removal of incidents, and through efficient traffic management during incidents. • Reduction of vehicular delay due to recurrent congestion through efficient traffic management. • Improvement of safety levels for motorists using the freeway by advising motorists of traffic and roadway conditions. • Reduction of energy consumption by achieving improved traffic conditions with reduced vehicular delay. • Incident duration • Vehicular delay • Secondary crashes • Quality of traffic flow • Diver response to Changeable Message Sign (CMS) messages. Table 2.4 - COMPASS Objectives and MOEs In this evaluation, safety benefits were attributed and limited to secondary crashes only, without recognizing the potential safety benefits that could be derived from the other measures such as Incident Duration and Quality of Traffic Flow. 2.2.2 Trans Canada Highway Monitoring & Evaluation Program In 1997, the Province of British Columbia developed a monitoring and evaluation framework for evaluating a planned pilot traffic management and traveller information system along the section of the Trans Canada Highways that goes through the Greater Vancouver area. This evaluation framework includes the application of a number of MOEs (presented in Table 2.5) for before and after evaluation purposes (BC MoT, 1997). 18 Objectives • . " MOEs" . • .. - . Reduce and Manage Recurring Congestion Travel Times Reduce & Manage Non-recurring Congestions Incident Durations & Delays Improve Safety Crash Rates & Crash Insurance Claims Optimize Efficient Use of Capacity Person Throughput Acquire Public Acceptance & Satisfaction Surveys Table 2.5 - British Columbia's Trans Canada Highway Objectives and MOEs Currently samples of "before implementation" data has been collected supporting all of the MOEs; however, the application of the framework has not yet been applied due to delays associated with the deployment of the pilot project. 2.2.3 ITS Evaluations in Texas Several ITS evaluations have been performed in the large urban areas of Texas, including Houston (TranStar), San Antonio (TransGuide), and Fort Worth (TransVision). Other estimates of ITS benefits have also been calculated in ITS planning studies in Dallas. The Texas Transportation Institute (TTI) has been conducting ongoing evaluations of the TransGuide traffic management system (TTI, 1998). TransGuide was deployed by the Texas Department of Transportation's (TxDoT) in July of 1995. TransGuide incorporates traffic management and traveller information applications designed to provide information to motorists about traffic conditions, such as incidents, congestion, and construction (TxDoT, 2002). Table 2.6 provides a summary of the MOEs used to evaluate the first 2 phases of the TransGuide project (TTI, 1998). 19 Category Measures of Effectiveness Phase I Phase II Safety Impacts accident rate accident severity accident type total accidents per vkt accident severity per vkt secondary accidents per vkt Recurrent Congestion/Traffic Operations travel delay fuel consumption vehicle emissions travel time travel speed travel time reliability/variability freeway main lane and ramp volumes Incident Management incident response time incident clearance time total incident duration incident response time incident clearance time incident queue dissipation time Driver Behaviour, Understanding, and Utilization comprehension of LCS and DMS compliance confidence and trust in system overall impression of the system behaviour during incidents perception of delays, system performance, and quality of information VIA Transit Operations schedule adherence/reliability express route and para-transit operating stats (e.g., on-time performance) San Antonio Police Operations not evaluated false alarm rate person- and vehicle-hours mobilized per incident crime statistics Incident-Related Diversion Characteristics not evaluated traffic volumes at arterial diversion route intersections traffic volumes on diversion freeways System Operator Perception not evaluated perception of TxDOT, SAPD, and VIA operators regarding system benefits and changes in job efficiency Source: Texas Transportation Institute, San Antonio, Texas. Table 2.6 - M O E s Used in the Evaluation of TransGuide TxDOT conducted analyses that estimate the benefits of incident management as conducted in the TransVision traffic management centre. The primary MOEs used in the evaluation included vehicle delay savings per incident, total delay savings, and annual dollar value of delay savings. These measures were calculated by using historical traffic volumes in a computer model and assuming various incident characteristics (e.g., incident occurrence and clearance times, queue clearance time, number of lanes affected, etc.). The impact of incident management on secondary incidents was identified but not quantified (TTI, 1998). 20 TTI staff in Dallas and Arlington developed the Dallas ITS Early Deployment Plan in cooperation with TxDOT and other regional transportation agencies. The proposed ITS deployment in Dallas was evaluated by using computer modeling and other prediction tools to estimate MOEs. The measures used to evaluate the proposed ITS deployment included reduction in crashes, reduction in delay and fuel consumption costs, and a benefit-to-cost ratio (TTI, 1998). 2.2.4 Washington State Two studies prepared by the Washington State Transportation Centre (TRAC) for the Washington State DoT and the US DoT provide discussions on attributing safety benefits to ITS applications in urban areas and in rural areas of Washington State. Although the discussions are presented in context of the transportation issues faced by Washington State, they provide a useful basis for evaluation purposes. In Technology and Safety in Urban Roadways: The Role of ITS for Washington State DoT (McCormack & Legg, 2000), the authors examine the relationship between ITS and safety by categorizing various ITS applications as a means of correlating them against the accrual of safety benefits. Specifically, the report groups ITS safety benefits according to two categories of ITS application (McCormack & Legg, 2000): • System Level: Examples cited under system level ITS applications include Freeway Management Systems (such as ramp metering, incident management, and traveller in information) and Traffic Signal Management, whereby safety benefits are attributed as a by-product of the primary objective of such applications which is smother flows, and reduced congestion and delays. 21 • Site Level: Examples cited under site level ITS applications relate to enforcement, work zones, hazardous locations and warning signs, and pedestrians, whereby obtaining safety benefits is the primary objective of the particular application. 2.2.5 US ITS Architecture ITS Performance & Benefits Study The ITS Performance & Benefits Study (US DoT, 1996) was one of the documents prepared as part of the US National ITS Architecture effort. The primary purpose of this document was to describe the connection between the National ITS Architecture and its technical performance characteristics relative to ITS planning and design; however, in recognition of the fact that ITS designs and implementations that are "enabled" by the ITS system architecture are ultimately intended to provide user benefits (illustrated in Figure 2.1), the document also includes a discussion of transportation system benefits from ITS. Figure 2.1 - Relationship Between System Architecture and ITS Benefits 22 While benefits associated with the performance characteristics of ITS system architecture (i.e. such as facilitating the development of standards) are not of relevance to this thesis topic, the manner in which the user benefits are presented and correlated against the architecture are of relevance, and provide a possible basis for developing an evaluation framework. Specifically, the user benefits section of this document uses the goals defined in the National ITS Program Plan (US DoT, 2000), prepared jointly by the US DoT and ITS America as a tool to help guide the development and deployment of ITS in the U.S. This plan includes six goals for ITS: 1. Increase Transportation System Efficiency & Capacity 2. Enhance Mobility 3. Improve Safety 4. Crude Energy Consumption & Environmental Costs 5. Increase Economic Productivity 6. Create an Environment for an ITS Market These goals are often referred back to within much of the ITS related literature in the US. The discussion of benefits in the ITS Performance and Benefits Study (US DoT, 1996) is in context of these goals. Specifically, a set of "benefits metrics" are used to qualify or quantify the broad goals referenced above. Table 2.7 provides a listing of the metrics associated with each goal. 23 ITS Gouls Related Metrics Increase Transportation System Efficiency and Capacity • Traffic flows, volumes, number of vehicles • Lane carrying capacity • V / C ratio • Vehicle hours of delay • Queue lengths • Number of stops • Incident related capacity restrictions • A V O • Use of transit and H O V modes • Intermodal transfer time • Infrastructure operating costs • Vehicle operating costs Enhance Mobility • Number of trips taken • Individual travel time • Individual travel time variability • Congestion and incident related delay • Travel cost • Vehicle miles travelled • Number of trip end opportunities • Number of crashes • Number of security incidents • Exposure to crashes and incidents Improve Safety • Number of incidents • Number of crashes • Number of injuries • Number of fatalities • Time between incident and notifications • Time between notification and response • Time between response and arrival at scene • Time between arrival and clearance • Medical costs • Property damage • Insurance costs Reduce Energy Consumption and Environmental costs • Emissions • Litres of fuel consumed • Vehicle fuel efficiency Increase Economic Productivity • Travel time savings • Operating cost savings • Administrative and regulatory cost savings • Manpower savings • Vehicle Maintenance and depreciation • Information gathering costs • Integration of transportation systems Table 2.7 - ITS Goals and Performance Evaluation Metrics 24 The ITS Performance and Benefits Study (FHWA, 1996) also provides a set of logical connections between the market packages in the US National ITS Architecture and the above referenced benefits metrics, and provides a preliminary causal inference of quantitative benefits for each market package. The tool used to correlate the relationship between the market packages and the metrics (and thus the ITS goals) is the benefits (or logic) flow diagram. Two set of benefit-flow diagrams are provided, whereby one set represents the linkages between the Market Packages and the metrics, while the second set presents the links both among the metrics themselves and between the metrics and the goals. Figures 2.2 and 2.3 (US DoT, 1996) provide one example of each of these diagrams respectively (it should be noted that the references to other figures in the diagrams below are in relation to the other benefit flow diagrams in the a source document and are not included in this thesis). Freeway Com ml Vehicle Hours of Delay Fis A.2-2 Lane Carrying Capacity FiH A.2-6 Number of Stops Fig A.2-8 Queue Length Fig A.2-7 Figure 2.2 - Benefit - Flow Diagram: Market Package to Metrics 25 • Exposure to Fig A.2-13 Accidents/Incidents Fig A.2-11 ^Insurance Costs Figure 2.3 - Benefit Flow Diagram: Metrics to Goals The benefit-flow diagrams provide a good starting point for understanding the context under which ITS benefits can be achieved; specifically, they relate ITS applications (market packages) to goals through a set of performance metrics and the manner in which they influence each other. 2.2.6 US DoT - ITS Benefits Database Since December of 1994, the US DoT's ITS Joint Program Office (JPO) has been actively collecting information regarding the impact of ITS implementations. This effort has been supported through the regular updating and compilation of the information in the following forms (Mitretek Systems Inc., 2001): • Periodical compilation in report format; the most recent being the ITS Benefits Update 2001 - as referenced herein (updated annually). 26 • The National ITS Benefits Database; this database is available to the public at www.benefitcost.its.dot.gov. The database contains the most recent data collected by the JPO (updated quarterly), and includes detailed summaries of each of the ITS evaluation reports reviewed by the JPO. Summaries on the web pages provide additional background on the context of the evaluations, the evaluation methodologies used, and links to the source documentation, i f available online. Both media provide a comprehensive summary of ITS benefits data for transportation professionals, while also providing the research community with information on ITS areas where further research and evaluations may be required. The benefits data reported by the JPO is categorized in terms of several Measures of Effectiveness (MOEs) identified to evaluate the performance of ITS services. Commonly referred to as "a few good measures", these MOEs consist ofN the following (Mitretek Systems Inc., 2001): • Crashes • Fatalities • Travel time • Throughput • Costs • Public satisfaction and acceptance. These MOEs were derived to support a number of ITS program goals established by the JPO in 1996. The goal areas include improving traveler safety, improving traveler mobility, 27 improving system efficiency, increasing the productivity of transportation providers and conserving energy while protecting the environment (Mitretek Systems Inc., 2001). The MOEs have been used by the JPO over the past several years for the classification and reporting of ITS benefits data. The MOEs provide a useful classification system, making referencing easy when only a particular criteria is of interest (such as with safety, as the case with this thesis). In addition to using the classification system, interested researchers can access document summaries classified by the location of the implementation, the performance measures reported for the projects, or relevant keywords using the on-line database. These capabilities of the online database simplify access to the most recently available data on ITS benefits identified by the JPO. The website also contains a discussion of the criteria and sources used to determine whether or not a report should be added to the ITS Benefits Database (Mitretek Systems Inc., 2001). 2.2.7 US DoT - Estimating Potential ITS Safety Benefits Using the ITS benefits data collected by the JPO, the US DoT commissioned a study in 1998 to estimate the potential safety benefits of ITS resulting from full implementation of ITS technologies in the US. The title of the report is Working Paper: Estimating the Potential Safety Benefits of ITS (Mitretek Systems Inc., 1998). While the actual estimates generated are not related to this chapter (and are presented along with other reported safety benefits in Chapter 3), aspects of the methodology used to generate the estimates provide some added insight in the current state of practice for evaluating ITS safety benefits. 28 The methodology used in this study involved the following approach: • Classification of ITS countermeasures that impact safety into three groups: (1) infrastructure based systems; (2) vehicle based systems; and, (3) cooperative systems (i.e., those ITS applications that require a combination of infrastructure and vehicle based systems - such as transit signal priority systems that require equipment on transit vehicles as well as on the road-side). • Identification of crash reduction factors for each ITS countermeasure grouped under the above mentioned categories. The crash reduction factors are derived from the reported ITS safety benefits data compiled by the JPO (as discussed in section 2.2.6). The study acknowledges that the limitations of this data, specifically highlighting that the majority of the reported benefits are based on simple before and after studies (not taking into account regression to the mean effects), and that most do not incorporate the use of control variables to take into account other non-ITS factors that may have impacted crash occurrence. • Allocation of confidence levels to the crash reduction factors associated with each ITS countermeasure used. Confidence levels are established based on the quantity and quality of data. Table 2.8 (Mitretek Systems Inc., 1998) provides a summary of the ITS countermeasures, crash reduction factors, and confidence levels used in the study. • Correlation of each counter measure with the crash type(s) affected (also presented in Table 2.8). For example, some of the countermeasures are labelled to impact only "rear-end" crashes, while many are labelled as impacting "all" types of crashes. 29 ITS Technology Type ITS Countermeasure Traffic Impacted Crash Type Impacted Crash Reduction Factor Value Level of Confidence Infrastructure-based R a m p Metering Urban Freeways All 2 4 % H Incident Detection Urban Freeways All 18% M Video Enforcement Urban Arterials All 2 0 % M Grade Crossing Enforcement Railroad Cross ings All 7 8 % L R W I S (snow/ice) Rural roads, inclement weather All 4 0 % L R W I S (fog) Rural roads, foggy conditions All 8 5 % L Vehicle-based Rear-end C A S • All Rear-end Crashes 4 8 % M Lane Change C A S All Lane change/merge crashes 3 7 % M Roadway Departure C A S All Single vehicle, run-off-road crashes 24% M Cooperative In-vehicle Navigation Systems Urban Arterials All 1% L Emergency Response (Mayday) Rural Roads , fatal only All 7% MIL Intelligent Speed Control Urban Freeways All 2 0 % L Table 2.8 - ITS Countermeasures, Crash Reduction Factors, & Confidence Levels Based on the above approach, national crash statistics (for the year 1995) are used as the basis of applying the crash reduction factors associated with each countermeasure to the total crashes (of the relevant type); percentages are then calculated by dividing the net reduction in crashes by their respective totals. Finally, the results are aggregated into the infrastructure based, vehicle based, and cooperative system categories. The result of the research is a high level estimate representing the percent reduction in annual fatal and injury crashes with full ITS implementation relative to the no-ITS baseline. Tables 2.9 and 2.10 provide a summary of the estimates (Mitretek Systems Inc., 2001). 30 ITS Area 1995 Injury Crashes Crashes Avoided % Crash Reduction Infrastructure-based 2,166,000 312,280 14.4% Cooperative 2,166,000 36,560 1.7% In-vehicle 2,166,000 299,810 13.8% Total 2,166,000 648,650 29.9% Table 2.9 - Estimated Percent Crash Reduction Factors for Injury Crashes in the US ITS Area 1995 Injury Crashes Crashes Avoided °/o Crash Reduction I nf rastru ctu re-based 37,241 4,163 11.2% Cooperative 37,241 1,589 4.3% In-vehicle 37,241 3,820 10.3% Total 37,241 9,572 25.7% Table 2.10 - Estimated Percent Crash Reduction Factors for Fatal Crashes in the US 31 3 S U M M A R Y O F B E N E F I T S R E P O R T E D T O D A T E The majority of existing research and reported benefits data is in terms of the broad ITS application area categories presented in Section 2.1.1. Only recently has the pursuit of a systematic way of evaluating ITS benefits resulted in the development of specific taxonomies for reporting ITS benefits. Since 1994, the US DoT's ITS Joint Program Office (JPO) has been actively collecting information on the impacts and benefits of ITS. The JPO's ITS Benefits: 1999 Update includes the use of a new taxonomy developed for classifying ITS benefits data. This taxonomy is based on two core deployment categories: intelligent infrastructure and intelligent vehicles, together covering all of the ITS application areas. Specifically, intelligent infrastructure comprises the family of technologies that enable the effective operation of ITS services in metropolitan areas, in rural settings, and for commercial vehicle applications, while the intelligent vehicles category centres around vehicle control and safety systems. Figure 3.1 presents the details of this taxonomy. Much of the existing ITS benefits data in North America is presented in the ITS Benefits: 2001 Update published by the JPO, using this taxonomy. Although the literature search conducted for this thesis included many additional references, this taxonomy has been used as the basis of presenting existing ITS safety benefits. 32 Intelligent Infrastructure'1 , Metropolitan Rural ITS/CVO < Arterial Management Systems , Crash Prevention & Security .Safety Assurance . Freeway Management Systems - Emergency Services ^Credent ia ls •Administration' - Transit Management ^ .Systems . • - Travel & • Tourism Electronic " * Screening _± Incident Management Systems ^Traf f ic Management -Carr ier Operations .. _^ Emergency . •.Management ^.Transit & "*Mobil i ty , , ... Electronic Toll Collection _^ Operations & Maintenance - Electronic Fare Payment » Road Weather Management ^H ighway-Ra i l ' ' ' Intersection . • Regional Multimodal Traveler Information . ' • ' ' ' . . v ' ^Information Intelligent Vehicles All Platforms Platform Specific Collision Avoidance _ Personal and Warning Vehicles .Other Driver Commercial ' Assistance Vehicles Transit ^Vehicle's . ' - ' - • ' ' ' ^Emergency and Special Use Vehicles Management Figure 3.1 - FHWA's ITS Benefits Taxonomy 3.1 Metropolitan ITS Infrastructure The metropolitan ITS infrastructure category is focused on ITS applications that are primarily deployed in urban and suburban areas, and includes the nine major components presented in Figure 3.1. Since the focus of many existing ITS deployments has been urban areas, this category is the most dominant in terms of available reported benefits data. 3.1.1 Arterial Management Systems These systems incorporate advanced traffic signal control systems to improve traffic flow, and automated enforcement systems to lower crash causing violations. Most of the referenced safety benefits relate to following three major areas of application: 33 3.1.1.1 Automated Red-Light Enforcement Systems A reduction in red-light running violations poses a strong safety benefit resulting from reduction of potentially severe crashes. Reported values of red light running violation reductions due to automatic camera enforcement include (Jernigan, 1998): • Howard County, Maryland, 23% • San Francisco, 30% (ITE, December 1999 reports 42% reduction) • New York City, 20% • Fort Mead, Florida, 50% • Jackson, Mississippi, 60% • Los Angeles, 92% & 78% (at two different rail crossings) • Charlotte, North Carolina, 75% (ITS International, 2000) • Oxnard, California, 42% (ITE, 1999) A number of agencies have also reported crash reduction benefits resulting from automated red-light violation enforcement: • Fairfax City, Virginia police reported a 35% reduction in overall crashes • Los Angeles, California, 43% reduction in red-light running crashes • London, reduction in injury crashes range between 20% to 80% when using cameras • Victoria, Australia, 15% to 32% reduction in crashes due to 35 cameras and 132 potential sites (ITE, 1999) 34 • Charlotte, North Carolina, 9% (ITS International, 2000) 3.1.1.2 Automated Speed Enforcement Automated speed enforcement typically incorporates radar technology coupled with automatic digital or 35mm film photographs to capture the licence plates of posted speed limit violators and fining them. In Natural City, California, a 51% reduction in crashes is attributed to an automated speed enforcement program involving 90 potential sites, and based on six years of before and six years of after data. In Paradise Valley, Arizona, a 40% reduction in city-wide crashes is attributed to a mobile automated speed enforcement since its inception in 1991 through to 1997. (ITE, 1999). A study of speed cameras in London, England, has reported a 20% reduction in injury crashes, and a 50% reduction in severe or fatal crashes on major arterials with speed enforcement cameras. (Coleman, 1996). In Australia, two separate implementations of speed enforcement cameras in South Wales and Victoria led to 22% and 30% reduction in crashes respectively (Mitretek Systems Inc., 1998). 3.1.1.3 Advanced Traffic Control Also relating to Arterial Management Systems, the Los Angeles Department of Transportation reports benefits of a signal management system, that adjusts to traffic conditions, to include 40% less stops at traffic signals, thus inferring safety benefits associated with congestion reduction (Jernigan, 1998). 35 Similarly, the FAST-TRAC project in Troy, Michigan, reports improved safety due to less stop-and-go conditions. This project included the implementation of the Sydney Coordinated Adaptive Traffic System (SCATS), whereby an 18% reduction in crashes was observed one year after system installation. It should be noted that the implementation did also include other non-ITS improvements such as the addition of protected left-turn phases which also would have contributed to the crash reduction factors reported. (Mitretek Systems Inc., 1998). Safety benefits of arterial management systems can extend to pedestrian operations at signalized intersections. A study by the University of North Carolina reports that the use of automated pedestrian detection devices, combined with traditional pushbuttons, results in fewer vehicle to pedestrian conflicts. Specifically, an 89% reduction in conflicts is reported for pedestrians during the first half of their crossing, as well as a 42% reduction during their second half of crossing. (Mitretek Systems Inc., 2001) 3.1.2 Freeway Management Systems Freeway management systems employ systems that incorporate surveillance and monitoring, traffic control and management, traffic and road information, as well as automated enforcement systems in order to maintain an optimum flow of traffic and thus limit conflict between traffic streams. The majority of the reported safety benefits correspond to the "control" function primarily through ramp metering. Studies for an F H W A report summarized the results of a number of case studies on ramp metering, citing crash reductions of ranging between 15% to 50% (Mitretek Systems Inc., 1998; Robinson & Piotrowicz, 1995). 36 Table 3.1 provides a summary of reported values (Mitretek Systems Inc., 1999): Location # of Ramp % Reduction in % Reduction in Meters Crashes Crash Rate Portland, Oregon 58 43% Minneapolis/St. Paul, Minnesota 6 24% Minneapolis/St. Paul, Minnesota 39 27% 38% Seattle, Washington 22 39% 42% Denver, Colorado 5 50% (Rear End & Side Swipe) Detroit, Michigan 28 8% Long Island, New York 70 15% Table 3.1 - Reported Safety Benefits of Ramp Metering A six year study comparing crash frequencies at nine ramp metering locations in Arizona found that overall, crashes increased by 24% during periods when ramp metering was in operation, versus 43% during periods when ramp metering was not in operation. The study also found that crashes occurring on the ramps increased during the period when ramp metering was in operation, due to vehicle stoppages at the ramp meter signals (Cleavenger et al, 1999). More detailed results from a study in Glasgow, reflect a 10% reduction in the number of vehicles merging too early, after the implementation of ramp metering; the study also reports a 5 to 7% reduction in the number of lane changes in the two lanes adjacent to the ramp (Allsopp, et al., 1998). Another reported safety benefits associated with freeway management systems is from the implementation of variable speed signs (enforced by cameras) by the United Kingdom Department of Transport who report crash reductions of 28% over an 18 month period (Mitretek Systems Inc., 1999). In the freeway management area, safety potentials have been realized in conjunction with roadside information systems that warn heavy vehicles, such as trucks, of hazards associated 37 with their speed and the road environment. Reported safety benefits of such truck warning systems include: • Implementation of Automatic Truck Rollover Warning Systems (ATRWS) at three sites along Washington D C s capital beltway. The system consists of a weigh-in-motion scale, height detection, and roadside processing to calculate the roll-over threshold speed for each truck in relation to the ramp curvature. Evaluation of the system has showed that the reduction in the speed of 500 trucks activating the signs was 22% higher than 252 trucks not activating the signs (McGee and Strickland, 1998). Two of the sites, those on the Maryland and Virginia freeways report a reduction of truck roll-over crashes from 10 (between 1985 and 1990) to zero between 1993 and 1997 (Mitretek Systems Inc., 1999). • Implementation of a Dynamic Truck Downhill Warning System (DTWS) along the 1-70 in Colorado showed a 13% reduction in associated crashes and 24 % reduction in the use of runaway ramps, over a 4 year period between 1993 and 1997 (Inside ITS, 1997). Reported benefits of warning systems extend beyond the speed related references above, and include benefits of weather related warning systems: • An automated motorist warning system in Ft. Lauderdale, Florida, which warns motorists of wet pavement conditions, has resulted in a 10.2 mph speed reduction during heavy rain conditions, and 4.6 mph reduction during light rain conditions (Pietrzyk, 2000). • An automatic fog signalling system on the A16 Motorway in the Netherlands, which displays lower speed limits during low visibility fog conditions, has resulted in 8 to 10 kph speed reductions (Hogema and van der Horst, 1995). 38 Finally, Shapiro et al. (1998) report an 11% reduction in peak period crash rates as a result of the application of traffic management systems for construction zones. 3.1.3 Incident Management Systems Incident management systems aim to minimize the impacts of traffic incidents through quick detection, coordinated response, and fast removal. Resulting safety benefits can be derived from three primary sources. Specifically: • Quick detection results in quick response, whereby responses can include warnings of an incident to upstream motorists and can lead to a reduction in secondary crashes. • Quick response results in the faster arrival of emergency medical services to an incident site, and thus lowering the chances of injuries becoming serious and life-threatening. • Together, quick detection and response result in an overall lower incident duration, minimizing the level of congestion due to the incident, as well as minimizing the probability of secondary crashes occurring. The most quantifiable safety benefit of incident management would be measuring a decrease in the number of serious injuries or fatalities resulting from faster detection and response to incidents. It is more difficult to correlate crash reductions to incident management alone, since systems are typically integrated with other freeway management system functions. Nevertheless, reported values include: 39 • Philadelphia, Pennsylvania's Traffic and Incident Management System reports 40% reduction in freeway incidents and an 8% reduction in incident severity rate (Mitretek Systems Inc., 2001) • The first phase of the TransGuide System reports 35% reduction in total crashes, 30% reduction in secondary crashes, and a 41% overall reduction in crash rates (Mitretek Systems Inc., 2001). • Japan's Hanshin Expressway reports a 50% reduction in secondary crashes due a significant reduction in incident detection times (Mitretek Systems Inc., 2001). • Toronto's COMPASS system reports a reduction of 11 % in secondary crashes (MTO, 1994). • The application of an automatic incident detection system with variable speed advisory signs along the M l motorway in the U K has resulted in an 18% reduction in total injury crashes, based on before and after data over a 7 year period (Mitretek Systems Inc., 1998). It has been estimated that in the event of a crash, the risk of a secondary crash is increased by 300 to 600%, since once a crash occurs, congestion, speed variance, and traffic stops increase (Jernigan, 1998). Another study estimates that the likelihood of secondary crashes occurring may have been reduced by 18.6% in the winter, and 36.3% in other seasons, due to Indiana's Hoosier Helper freeway service patrol (Karlaftis, 1998). Finally, observed reductions in the duration of incidents can also provide a reference for safety benefit potential. For example, using data from 2,645 incidents and the CORSLM 40 model, a 35% reduction in incident duration is attributed to the Maryland State CHART Highway Incident Management System (Chang et al., 2000). 3.1.4 Emergency Management These systems can be considered as extensions of, or dependent on, incident management systems and employ technology applications for dispatch, fleet management, and route guidance. Safety benefits result from reduction in response times from emergency services that in turn can result in a reduction in fatalities or severe injuries once a crash has occurred. In this regard, a study by Brodsky and Hakkert (1983) reports that an 11% reduction in fatalities as a result of an 8.45 minute reduction in response time. 3.1.5 Regional Multi-modal Traveller Information Advanced Traveller Information Systems (ATIS) represent one area where little to no safety related benefits results is available. ATIS has the potential to provide safety benefits, derived from "diversions" either in time, space, or mode, which can result in lower levels of congestion, and therefore crashes. In this context, a diversion in time infers delaying or rescheduling of trips in order to avoid congestion, a diversion in space infers a change in routing between origin and destination, and a diversion in mode infers mode change. A European study has found that road and weather monitoring systems are successful in reducing vehicle speeds by up to 10%, crash rates by more that 30%, and fatal crashes by 40% during inclement conditions (Mitretek Systems Inc., 1998). 41 3.1.6 Transit Management Advanced Public Transportation Systems (APTS) include a number of ITS applications that can help transit agencies increase the safety and operational efficiency of their systems. Transit ITS services assist operators in maintaining vehicle fleets; self-diagnostics of vehicles can alert of unexpected mechanical problems as well as routine maintenance needs. Automated vehicle location (AVL) and computer aided dispatch (CAD) can improve scheduling activities and schedule adherence. Finally, remote monitoring of transit vehicle status and passenger activity helps to provide additional safety and security to passengers. While much of the reported benefits data in this area relates to on-time performance, schedule reliability, and overall operational efficiency, some security related safety benefits have been reported. Since implementing an Automatic Vehicle Location (AVL) system, the Denver Regional Transportation District (RTD) reports that the provision of a silent alarm feature with the A V L system has helped improve the safety of the transit system, whereby passenger assaults per 100,000 passengers decreased by 33% between 1992 and 1997 (Mitretek Systems Inc., 2001). 3.2 ITS Infrastructure in Rural Areas Transportation challenges in rural areas are very different than in urban areas. In Canada, although rural areas represent small population areas, they cover major stretches of the transportation system. In the US, eighty percent of the total road mileage is in rural areas, generating 40% of the vehicle miles traveled (Mitretek Systems Inc., 2001). Unlike urban areas, the rural environment has a different set of priorities and needs that reflect longer distances, lower traffic volumes, higher speeds, drivers unfamiliar with the surroundings, and 42 longer emergency response times. Many of the ITS services provided in metropolitan areas can also be implemented in the rural environment; however, these services are sometimes required to cover much broader areas, or may become much more specialized in what they provide to the traveler. Rural ITS initiatives are relatively new, but have had increasing activity and funding levels over the last few years. In the US, many rural operational tests and early deployments are currently underway. Some of these tests are starting to report impacts and benefits, while many are still undergoing development, implementation, or evaluation. Using the taxonomy provided in the ITS Benefits: 2001 Update (Mitretek Systems Inc., 2001), the key elements of rural ITS infrastructure are Traveller Safety & Security; Emergency Services; Tourism & Travel Information; Public & Travel Mobility Services; Infrastructure Operations & Maintenance; Fleet operation & Maintenance. Surprisingly, although a potential safety benefit exists in Traveller Safety & Security, and Emergency Services, no benefits data is presented in the 2001 update. A study of three years (1993 to 1996) of rural crash characteristics in Washington State reports that although the total rate of crashes (per million miles of travel) in rural areas was almost half as much as in urban areas, the fatality rate was almost three times higher. Table 3.2 provides a summary of contributing crash factors, rural issue, and percent of vehicles, from this study (McCormack and Legg, 1999). The study does not include any crash reduction estimates, but does provide corresponding ITS countermeasures to the causes cited. 43 Contributing Crash Factor Cause %o"f Vehicles | Road Environment Driver (Human Factors) Vehicle Unsafe speed or exceeding speed limit Inattention or sleeping Judgement errors Drug or alcohol Other human factors Weather Wildlife Work zone Other road hazards Pedestrian or bicycle involvement Railroad crossing Rural intersection Truck involvement 22% 9% 16% 5% >0.5% 23% 5% 3% >0.1% 0.7% 1% 28% 7% Table 3.2 - Summary of Rural Crash Causes Versus Percent Vehicles Jernigan (1998) references potential benefits that may be derived from Mayday systems that facilitate the quicker detection, and shorter response time of rural incidents that may be difficult to detect and locate. Referencing an observed 5.2 minute reduction in the detection of incidents in one rural area, fatal crashes could be reduced by up to 7% (assuming that 60% of rural crashes would be detected faster). Mitretek Systems Inc., (1996) reported a potential 12% increase in an occupant's chance for survival, based on a simulated 43% decrease in response times due to mayday system notifications. A statistical study conducted over 48 US states reports that is crash notification times are reduced by 50% in rural areas, a 7% reduction in rural fatalities can be expected (Mitretek Systems Inc., 1998). In field tests conducted on the Ford-Lincoln Continental Remote Emergency Satellite Cellular Unit (RESCU) security system, drivers were able to make voice contact with a 44 response centre operator within one minute. On average, emergency response vehicles arrived within 11 minutes of system activation (Mitretek Systems Inc., 2001). 3.2.1 Emergency Services A study of a radar based curve-warning system installed at 5 sites along the 15 in rural California found a statistically significant reduction in truck speeds after the installation of the system. Three of the five sites had significant reductions in speed, in at least on of the three post-implementation Visits (2, 5, and 10 months), while two sites had significant reduction during all three of the post periods analyzed; however, speed reductions (although significant) were less in subsequent visits (Tribbett, et al., 1999). A rural stop-controlled intersection warning system that uses loop detectors to activate signs warning traffic of the presence and direction of conflicting traffic resulted in the elimination of critically short Projected Time to Collision (PTC), for speed violators, after implementation (Hanscom, 2000). 3.3 ITS for Commercial Vehicle Operations (CVO) Safety related benefits of ITS applications to C V O form a key component of expected benefits; due to the larger mass of heavy commercial vehicles, the risks associated with crash severity and fatality are higher when crashes occur. Furthermore, since the potential for crash occurrence is as much a function of the vehicle, as the road and the driver, ITS applications to C V O are expected to help improve safety. There is, however, a lack of safety related evaluation results currently available. Most of the documented benefits of ITS applications to C V O relate to financial benefits gained by regulators and operators. 45 The taxonomy, for reported benefits related to ITS / C V O applications used in the ITS Benefits: 2001 Update (Mitretek Systems Inc., 2001) is comprised of Safety Assurance; Credentials Administration; Electronic Screening; and, Carrier Operations. Safety benefits are primarily expected from the better exchange of safety related data so that unsafe drivers and vehicles are identified and removed from the roadway more quickly. This exchange of data then extends to other applications such as electronic screening of vehicles, whereby compliant vehicles are permitted to bypass inspection stations, while resources are more focused to the non-compliant vehicles. Most of the current ITS / C V O benefits are "expected" estimates. In the area of Safety Assurance, Jernigan (1998) reports: • A n "early information network" in Oregon led to an increase of 90% more truck weightings, and 428% more safety inspections, even though there was a 23% reduction in staff. • A study of 10 states in the US Midwest reports that ITS applications to C V O is permitting safety inspectors to remove 50% more drivers and vehicles from service as compared to with conventional methods. Since sideswipe, angle, and rear-end crashes account for more that 75% of large truck crashes on Virginia's rural roads, with driver related failures accounting for 70% of them; on-board radar vehicle detection and driver alert systems are also expected to reduce these types of crashes (Jernigan, 1998). 46 3.4 Summary of Benefits Referenced Based on the literature reviewed and presented above, a tally can be made with respect to the number of safety benefit references for the different ITS application areas considered. Based on the taxonomy used in the previous section, the following tables tabulate the number of references for each application area, along with a subjective indication of the potential for safety benefits associated with that application area. Table 3.3 cites the number of references found for safety benefits associated with metropolitan ITS infrastructure application areas. Category Application Area ,7 of References Potential Arterial Management Traffic control; enforcement; 21 High Freeway Management Traffic control (ramp metering); enforcement; 17 High Transit Management Passenger security; vehicle maintenance 1 Low Incident Management Incident detection & response 9 High Emergency Management Incident Response 1 High Electronic Toll Collection Traffic control 0 Low Electronic Fare 0 N / A Highway-Rail Intersection Warning systems 0 High Traveler Information Demand management 1 Low Table 3.3 - Number of References for Metropolitan ITS Infrastructure Safety Benefits For metropolitan ITS infrastructure application areas, the frequency of references is generally proportional and consistent with the safety potential except in the area of Emergency Management where a high potential is expected but only one reference was found, and in the area of Highway - Rail Intersection Safety where no references were found. 47 Table 3.4 cites the number of references found for safety benefits associated with rural ITS infrastructure application areas. Category Application Area // of Potential References Traveller Safety & Security; Mayday systems; warning systems 5 High Emergency Services; Incident detection & response 1 High Tourism & N / A Travel Information; Public & N / A Travel Mobility Services; Infrastructure Improved roadway maintenance Medium Operations & Maintenance; Fleet operation & Improved vehicle performance Low Maintenance. Table 3.4 - Number of References for Rural ITS Infrastructure Safety Benefits For rural ITS infrastructure application areas, the total number of references is much less; and, again, for the high potential area of Emergency Services only one reference was found. In addition, no references were found for safety benefits associated with Infrastructure Operations & Maintenance systems that have the potential to improve safety through quicker response to fixing hazardous roadway conditions. Table 3.5 cites the number of references found for safety benefits associated with ITS / C V O application areas. Despite the potential, there is a significant lack of reported benefits in the area of ITS applications for C V O safety assurance. 48 Category Application Area #of References Potential Safety Assurance Regulatory safety information exchange 2 High Credentials Administration N / A Electronic Screening Safety screening 0 Low Carrier Operations H A Z M A T incident response 0 Medium Table 3.5 - Number of References for Metropolitan ITS Infrastructure Safety Benefits Chapter 4 provides a detailed discussion of the issues pertaining to the current knowledge base associated with the safety benefits of ITS. 49 4 ISSUES The previous sections have described current ITS terminology, current evaluation practices, and reported ITS safety benefits compiled from existing literature. Review of this literature suggests that although the potential safety benefits of ITS are well recognized by the ITS community, there is a deficiency in supporting evaluation results to establish this potential; this deficiency relates to both quantity, as wells as quality and reliability of benefits reported to date. The following sections discuss the issues associated with this deficiency. 4.1 Terminology It is evident from the literature that the reliability of existing evaluations of ITS benefits is compromised due to the lack of a consistent terminology for discussing ITS application areas. The lack of a common language for evaluating different ITS application areas has resulted in an inconsistency in the reporting of benefits, whereby measured results are attributed to different functional areas of ITS, and without regard to the level of integration between different applications areas. For example, in ITS Benefits: Success in the Field (ITS Quarterly, 1997) the safety benefits (in terms of crash reduction percentages) of a collision warning system is attributed to Advanced Rural Transportation Systems (ARTS); comparatively, in Expected Safety Benefits of Implementing Intelligent Transportation Systems in Virfiinia: A Synthesis of the Literature (Jernigan, 1998) the same benefits are attributed to Advanced Vehicle Control and Safety Systems (AVCSS). Similarly, the reduction benefits of the TransGuide project in San Antonio have been attributed to both freeway management systems (ITS Quarterly, 1997) as well as incident management systems (Jernigan, 1998). 50 While these references are cited with supporting details that attribute observed benefits to the application areas considered, they fail to recognize that, for example, the benefits associated with freeway management systems and incident management systems are inter-related. The overlap in results and inconsistencies in attributing to ITS application areas can be perceived as a discrepancy and leaves the researcher questioning the credibility of the reported benefits since they can be attributed to different ITS application areas. The use of a common reference of ITS application area categories is therefore critical in compiling reported benefits data as systems are deployed and evaluated. The Canadian ITS Architecture provides a common language for the planning and design of ITS. The language of the architecture could provide a useful basis for evaluating ITS benefits. 4.2 Gaps in Knowledge Irrespective of some inconsistencies in the manner in which ITS benefits data is reported, gaps in knowledge exist. This gap in knowledge is primarily the function of the extent of deployment in the ITS application areas with a safety benefit potential, the lack of evaluation data associated with existing deployments, and the lack of a framework for carrying out evaluations. 4.2.1 Extent of Deployment There are areas of ITS that have not experienced wide spread deployment, and as a result are difficult to evaluate in terms of real-life benefits. This is particularly true for many in-vehicle applications (such as collision avoidance systems) which are still in the research and development stages. 51 Other emerging application areas that are beyond research and development, also suffer from a lack of deployment. For example, in the area of CVO, ITS applications are increasing rapidly in the US, and emerging in Canada; however, the extent of deployment has not reached a level that can be evaluated or generate benefit results. As the level of deployment in these application areas is increased, the availability of a framework for evaluating safety benefits wil l be important in establishing associated benefits. 4.2.2 Lack of Evaluation Data Where there is wide spread deployment in a particular ITS application area, there is still a lack of supporting reliable evaluation data - as clearly demonstrated in the previous chapter. This lack of data can be attributed to following reasons: • lack of funds for carrying out evaluation studies; • undertaking of an evaluation study is often an "after thought" and difficult to do due to the lack of "before data" samples; • differences between the quantity and quality of the before and after data; • lack of a framework for measuring benefits. The ITS Benefits: Data Needs Update 2000 (Mitretek Systems Inc., 2000), prepared in conjunction with a workshop held by the Benefits Evaluation and Cost (BEC) committee of ITS America (August 2000) identifies ITS application areas where gaps or limited knowledge exists about their benefits. The gaps that are highlighted to show where there is little data collected to measure a particular ITS service. Table 4.1 provides a summary of the 52 number of safety related references currently in the FHWA's ITS benefits database (as of June of 2000). Application Area Total # of Safety Related References References Metropolitan ITS Infrastructure Arterial Management Systems 24 8 Freeway Management Systems 15 10 Transit Management Systems 9 3 Incident Management Systems 12 1 Emergency Response 5 5 Electronic Toll Collection 5 5 Electronic Fare Payment 3 0 Highway - Rail Intersections 2 2 Regional Multi-modal Traveller Information 8 0 Information Management 0 0 Rural ITS Infrastructure Crash Prevention & Security 1 1 Emergency Services 0 0 Travel & Tourism 0 0 Traffic Management 1 1 Transit & Mobility 3 0 Operation & Maintenance 3 1 Surface Transportation Weather 1 0 Table 4.1 - Summary of Safety Related Benefits Data in the FHWA's Database The above summary illustrates that out of a total pool of 83 benefit references, 37 relate the safety benefits of ITS applications. This is clearly not enough because the references are distributed among the different ITS services that fall under the above categories, are diluted due to overlaps in reported benefits and inconsistent terminology, and suffer from poor sample sizes and ad hoc evaluation methods. 4.2.3 Lack of a Framework The final issue relating to the gaps in the current knowledge base is the lack of a consistent framework for evaluating ITS applications and reporting benefits. The evaluation practices 53 and frameworks described in section 2.3 each have their own strengths and weaknesses, as summarized in Table 4.2. Evaluation Methodology Pros Cons . COMPASS (Section 2.2.1) • Detailed methodology with clearly established evaluation measures. • Comprehensive data collection including incident duration data. • Project specific • Only reduction in secondary crashes considered • Based on simple before and after comparisons of crash frequency. Trans Canada Highway (2.2.2) • Detailed methodology developed during project planning stage, with clearly established evaluation measures. • Comprehensive data collection incident duration data. • Project specific • Developed framework was not tested because the project was cancelled. • Poor quality crash data. ITS Evaluations in Texas (2.2.3) • Detailed methodology with clearly established evaluation measures. • Limited actual quantification of results. • Project Specific. Washington State (2.2.4) • Useful categorization of ITS applications based on their "contributing factors" to safety improvement. • Not an actual evaluation framework. US ITS Architecture Performance & Benefits Study (2.2.5) • Correlates market packages with evaluation metrics, while identifying contributing factors towards safety improvement. • Correlation of market packages to metrics not presented as a means of measuring ITS safety benefits, but rather, evaluating the 54 Evaluation Methodology Pros Gons • Development of benefit-flow diagrams. benefits of the architecture. US DoT Benefits Database (2.2.6) • Useful database where benefits data associated with • Not an actual evaluation framework. each of the National ITS • Uses a taxonomy and Program Plan's goals are classification system that is published. not consistent with the US ITS • Useful repository of ITS safety evaluations compiled by the JPO. Architecture. US DoT Estimating Potential ITS Safety Benefits • Provides a framework for estimating safety benefit of ITS assuming a 100% build • Notion of 100% build-up of ITS is hypothetical and not practical. up of ITS. • Confidence levels assigned • Introduces the idea of are not used. assigning confidence levels • The same crash reduction to existing evaluation results. factors are used to on the fatal crashes as the injury crashes. Table 4.2 - Pros and Cons of Existing Evaluation Methodologies Based on the above, it can be summarized that the strong attributes of current practices include the use of detailed evaluation methodologies and MOEs, as well as categorization of ITS application areas by the manner in which they contribute to benefits. Similarly, the weak attributes of current practices relates to project specific methods and MOEs, and use of inconsistent terminologies for categorizing ITS and its benefits. 55 4.3 Problem/Need Statement Summary It is apparent that i m p r o v i n g safety is a fundamental goal o f I T S ; however, it is also apparent that our a b i l i t y to c l e a r l y establish the manner and magnitude b y w h i c h I T S appl icat ions can help achieve this goal is deficient. T h e p r i m a r y issues affecting this de f ic iency have been ident i f ied as f o l l o w s : • R e a l benefits can o n l y be quanti f ied for I T S applications that are actual ly deployed, w h i l e p lanned deployments can o n l y be evaluated i n terms o f expected benefits either through s imulat ion or forecasting etc. • T h e evaluat ion o f an I T S appl icat ion area should be p lanned so that appropriate "before d e p l o y m e n t " data samples can be col lected. • I n p l a n n i n g the evaluation o f an I T S appl icat ion , an evaluation f ramework is required to ensure that the "before d e p l o y m e n t " statistics col lected w i l l support the actual downstream evaluat ion subsequent to deployment . • In order to be able to c o m p i l e and compare benefits results f r o m increasing I T S deployments i n one appl icat ion area, the evaluat ion framework must be based o n consistent t e r m i n o l o g y so that specif ic benefits can be c lear ly attributed to specif ic appl icat ions. • M o s t o f the evaluations to date have focused o n the def ini t ion o f system/project goals mapped to a set o f M O E s to measure the extent to w h i c h goals are achieved. T h i s process has l a c k e d the use o f a t e r m i n o l o g y that c lear ly defines the I T S appl icat ion that is b e i n g evaluated against attaining speci f ic goals. F o r example there is no clear reference that indicates the safety benefits o f R o a d and Weather Informat ion Systems 56 (RWIS), because some agencies may have reported it as ATIS, others as A T M S , and yet others as just merely RWIS. The Canadian ITS Architectures presents a good opportunity for establishing an evaluation framework that is based on consistent terminology of ITS application areas. 57 5 P R O P O S E D E V A L U A T I O N F R A M E W O R K The previous sections have presented past and present ITS terminologies, summary of reported ITS safety benefits, and review of the current practices in evaluating ITS applications, along with issues associated with each. Based on this research, the purpose of this chapter is to develop and present a framework for evaluating ITS safety benefits using the Canadian ITS Architecture as a basis. The process used to develop and present this framework has involved the following major steps (also summarized in Figure 5.1): • Description of the "Market Packages" in the Canadian ITS Architecture, supported by a discussion that highlights the areas of difference between the market packages in the Canadian ITS Architecture and the US National ITS Architecture. • Identification of a set of evaluation "metrics" that capture the flow of ITS safety benefits in terms of "causes" and "effects" that ultimately result in less crashes, with lower levels of severity. • Mapping of the market packages in the Canadian ITS Architecture to the "cause" and "effect" metrics, thus illustrating how each market package contributes to safety benefits. • Presentation of a summary and overview of the framework, supported by a set of guidelines for its application. • Identification of the benefits of the framework over existing practices relating to the evaluation of ITS safety benefits. 58 Canadian ITS Architecture Market Packages Cause & Effect Metrics for Measuring ITS Safety Benefits Mapping Market Packages to Metrics Framewori & Appl Guide : Summary ication ;lines r Framework Benefits Figure 5.1 - Framework Development Process 5.1 Market Packages in the Canadian ITS Architecture As noted in Chapter 2.0, the User Services and User Sub-Services of the Canadian ITS Architecture define what ITS should achieve from the perspective of the users of the transportation system. Market packages, on the other hand, help describe the parts (physical subsystems) of the architecture that are required to implement User Sub-Services. According to the Canadian ITS Architecture documentation (Transport Canada, 2001), Market Packages provide an accessible, deployment-oriented perspective to the Canadian ITS Architecture. Through the architecture, market packages identify the physical pieces that 59 are required to implement a particular transportation service. In this regard, market packages are developed to fit, separately or in combination, real world transportation problems and needs - thus making them a good basis for evaluating associated benefits relative to how those problems and needs are addressed. The Canadian ITS Architecture includes a total of 79 Market Packages. Of these 79 Market Packages, 16 new Market Packages were developed, and 6 were modified from the US National ITS Architecture, to address the new User Services of the Canadian ITS Architecture (Transport Canada, 2000). Table 5.1 provides a summary of all of the market packages that were modified or are new. Appendix A , provides a listing of all the market package in the Canadian ITS Architecture. Market Package Market PackageName-V-'-^ "^ "^  ^ .Comparison^ APTS 9 Multi-Modal Connection Protection New ATIS 1 Broadcast Traveller Information Modified ATIS 2 Interactive Traveller Information Modified A T M S 1 Traffic Network Flow Monitoring Modified A T M S 8 Incident Risk Prediction System Modified A T M S 20 Roadway Environmental Sensing New A T M S 21 Roadway and Weather Data Fusion New A T M S 22 Environmental Information Dissemination New A T M S 23 Roadway Micro-Prediction New A T M S 24 Infrastructure Maintenance Management New A T M S 25 Smart Work Zones New A T M S 26 Dynamic Roadway Warning New A T M S 27 Variable Speed Limit and Enforcement New A T M S 28 Signal Enforcement New A T M S 29 Mixed Use Warning Systems New A T M S 30 Automated Non-Vehicular Road User Protection New C V 0 5 International Border Crossing Clearance Modified C V O 11 Freight In-Transit Monitoring New C V O 12 Freight Terminal Management New E M 1 Emergency Response Management Modified E M 4 Disaster Command and Control New E M 5 Disaster Information Dissemination New Table 5.1 - New or Modified Market Packages in the Canadian ITS Architecture 60 5.2 Identifying the Metrics of the Framework This section identifies the set of metrics that can be used for evaluating the safety benefits of the market packages in the Canadian ITS Architecture. The approach used to establish metrics follows a similar approach to the metrics and benefit flow diagrams identified for the US ITS Architecture (discussed earlier in Chapter 4). Here, the metrics are refined and simplified to shift the emphasis from evaluating the safety goal alone, as opposed to all the other goals ITS is intended to help achieve. In addition, the metrics identified herein are different from the US metrics in that they must support the evaluation of the market packages in the Canadian ITS Architecture (which includes the incorporation of enforcement applications, and the enhancement of some of the road, weather, and vehicle warning applications). Table 5.2 presents the metrics identified for this evaluation framework. h'lC|iu||??.:Metrics' V .Effecti^ yletrics"''. • Driver Errors • Number of Crashes • Driver Violations • Severity of Crashes • Congestion • Exposure to Hazards • Mechanical Failures • Traffic Volumes • Inadequate / Reduced Capacity • Undetected Weather Conditions • Presence of Incidents • Incident Response & Clearance Times • Incident Detection Times Table 5.2 - Cause & Effect Metrics 61 As noted in Table 5.2, the metrics have been grouped into two categories called "Cause Metrics" and "Effect Metrics". These categories were defined to distinguish between the following: • "effect" represents the category of metrics that quantify the desired result, which in the case of safety is the reduction of crashes, and the severity of crashes when they do occur; • "cause" represents the category of metrics that quantify other contributing factors that affect the occurrence of crashes and/or their severity. As an example of the above categorization, congestion can be considered as a "cause" metric. Since the level of congestion can affect the occurrence of crashes, the direct measurement of a reduction in congestion (as a metric) can also represent a safety benefit. Figure 5.2 provides a summary of these metrics and their relationships using a "cause and effect" diagram, while also illustrating how some of the "cause" metrics referenced above can have contributing factors of their own. Where applicable, the "cause" metrics have been further classified in accordance to the three fundamental contributing factors to crash occurrence: the road environment; the driver; and, the vehicle. In the road environment, the primary "causes" that contribute to the occurrence of crashes are congestion and exposure to hazards. Similarly, drivers can cause crashes either through errors and violations, while vehicles contribute to crashes when they malfunction. 62 As illustrated in Figure 5.2, the primary road/environment, driver, and vehicle "causes" have their own contributing factors which can act as supporting metrics. Specifically, congestion can be measured in terms of traffic volumes (demand) and capacity. Therefore, a quantified measurement of either of these two contributing factors can be used to measure changes in congestion level and correlated to changes in the crash metric. Similarly, exposure to hazardous conditions is a function of undetected/reported weather hazards, or the presence of incidents such as the existence of crashes or debris which adversely affects the road environment. 5.3 Mapping of the Market Packages to the Metrics The following sections provide a discussion of the market packages in the Canadian ITS Architecture focusing on areas where safety benefits can be accrued. The discussion is based on a "counter-measure" approach; i.e., ".. .what does a particular market package counter that it leads to a particular safety benefit?" The discussion is then used to identify metrics that can be used to evaluate the benefit areas identified. In some cases, the Market Packages are grouped in accordance to the "bundles" in the Canadian ITS Architecture (defined in Section 2.1.3 of this thesis). However, where required, new categories have been defined to provide a smaller and more logical grouping of Market Packages for mapping to the metrics. 5.3.1 Advanced Traveller Information Systems (ATIS) The Canadian ITS Architecture includes nine market packages under this category. These market packages are presented in Table 5.3, and cover a broad range of ATIS functions from 64 broadcast and interactive traveller information services, to route guidance information services, through to in vehicle signing systems. ID Market Package ATIS 1 Broadcast Traveller Information ATIS 2 Interactive Traveller Information ATIS 3 Autonomous Route Guidance ATIS 4 Dynamic Route Guidance ATIS 5 ISP Based Route Guidance ATIS 6 Traffic Estimation and Prediction ATIS 7 Traveller Services Payment and Reservation ATIS 8 Ride Matching ATIS 9 In Vehicle Signing Table 5.3 - ATIS Market Packages Traveller information systems can benefit travellers prior to making their trip, and while en-route. Generally, ATIS applications provide information on prevailing traffic, road, and weather conditions. Travellers receiving this information prior to making their trip can avoid areas of congestion as well as hazardous road and weather conditions, by choosing a different mode, route, or time of travel. More importantly, travellers already en-route, can use the information to change their route or actually take precautionary measures based on a particular hazard close by. The safety benefit of these applications generally relates to travellers being able to "avoid" crash causing hazardous conditions. These conditions can be as common as non-recurrent congestion during peak hours, whereby motorists diverting to avoid such congestion are reducing the probability of crashes caused by congestion; or, conditions such as ice on a bridge, whereby an upstream Dynamic Message Sign can advise approaching motorists of the condition, causing them to take necessary pre-cautions. 65 With reference to Figure 5.2, it can be generalized that ATIS have the potential to impact two "streams" along the cause and effect flow chart. The first being the traffic volumes, congestion, and crashes stream, and the second being exposure to hazards, and crashes stream. While these can be used as metrics for measuring the safety benefits of ATIS, their application is not simple. The data for these metrics need to distinguish between conditions regarding which ATIS information was being disseminated, versus regular conditions. For example, to use traffic volumes to measure the safety benefits of a weather information system, one must compare traffic volumes (before and after the implementation of the system) collected during hazardous weather conditions. 5.3.2 Advanced Traffic Management Systems The Canadian ITS Architecture includes thirty market packages under this category. These market packages cover a multiplicity of areas relating to monitoring and data management, general traffic management systems, information and warning systems, and enforcement systems. These categories have been defined for the purpose of this framework because the "Traffic Management" bundle of the Canadian ITS Architecture is too broad. The implications of these categories to the framework are discussed further in section 5.4). Monitoring and Data Management - Market packages relating to this category are presented in Table 5.4. These market packages provide for basic traffic and roadway conditions monitoring capabilities. These market packages do not provide direct safety benefits, rather they facilitate the collection of and management of data required to support other market packages describes in the other categories (for example, loop detector data from the Traffic Network Flow Monitoring market package is used by incident detection 66 algorithms in the Highway Control market package). As such they are not mapped to any of the metrics established for evaluating ITS safety benefits. ID Market Package A T M S 1 Traffic Network Flow Monitoring A T M S 2 Probe-Based Flow Monitoring A T M S 8 Incident Risk Prediction System A T M S 9 Predictive Demand Management A T M S 11 Emissions Management A T M S 12 Virtual T M C and Vehicle-Based Sensing A T M S 15 Modal Operations Co-ordination A T M S 21 Roadway and Weather Data Fusion A T M S 23 Roadway Micro-Prediction Table 5.4 - ATMS: Monitoring and Safety Market Packages General Traffic Management - Market packages relating to this category are presented in Table 5.5. These market packages provide for basic arterial and freeway traffic management functions, as well as more specialized traffic management functions relating to H O V lanes, reversible lanes, toll collection, construction zones, and parking. It can be generalized that these market packages use real-time information (obtained from the monitoring and data management market packages described above) to optimize the available capacity in a way that better serves prevailing demands (whether on an arterial, highway, toll collection point, or parking lot). For example, the Surface Street Control market package may incorporate adaptive traffic signal control functions that optimize the allocation of green time based on demand; or, the Reversible Lane Management market package can serve directional peak flows better. On this basis, and with reference to Figure 5.2, the source of safety benefits that can be accrued from these market packages is largely related to the "inadequate/reduced capacity" metric. 67 ID Market Package A T M S 3 Surface Street Control A T M S 4 Highway Control A T M S 5 HOV Lane Management A T M S 7 Regional Traffic Control A T M S 10 Electronic Toll Collection A T M S 13 Basic At-Grade Crossing Control A T M S 14 Advanced At-Grade Crossing A T M S 16 Electronic Parking Payment and Parking Facility Management A T M S 17 Reversible Lane Management A T M S 19 Regional Parking Management A T M S 24 Infrastructure Maintenance Management A T M S 25 Smart Work Zones Table 5.5 - ATMS: General Traffic Management Market Packages Road and Traffic Information & Warning - Market packages relating to this category are presented in Table 5.6. These market packages expand on the basic arterial and freeway traffic management functions by using the real-time information (obtained from the monitoring and data management market packages described above) to warn motorists and pedestrians of imminent hazards. For example, Traffic Information Dissemination and Road Weather Information System market package can inform motorists of a downstream incident or icy conditions on a stretch of road, permitting the motorists to take necessary actions such as slowing down or diverting to another route. Similarly, the "at-grade crossing" market packages can warn vehicles of a potential conflict with a train, while the Automated Non-Vehicular Road User Protection market package incorporates systems that warn pedestrians and cyclists of hazardous conditions. On this basis, and with reference to Figure 5.2, it can be generalized that these market packages relate to the traffic volumes and exposure to hazardous conditions metrics. 68 ID Market Package A T M S 6 Traffic Information Dissemination A T M S 18 Road Weather Information System A T M S 20 Roadway Environmental Sensing A T M S 22 Environmental Information Dissemination A T M S 26 Dynamic Roadway Warning A T M S 29 Mixed Use Warning Systems A T M S 30 Automated Non-Vehicular Road User Protection Table 5.6 - ATMS: Information Warning Market Packages Enforcement - Market packages relating to this category are presented in Table 5.7. These market packages provide for specific applications of ITS technologies for the purposes of enforcing traffic signal regulations (i.e. red light running) and speed limits. These applications can improve safety by reducing hazardous conditions caused by driver violations. As such, and with reference to Figure 5.2, they can be mapped to metric of "driver violations". ID Market Package A T M S 27 Variable Speed Limit and Enforcement A T M S 28 Signal Enforcement Table 5.7 - ATMS: Enforcement Market Packages 5.3.3 Advanced Public Transportation Systems The Canadian ITS Architecture includes nine market packages under this category. These market packages are presented in Table 5.8, and cover all of the areas associated with technology applications to public transportation systems such as Transit Vehicle Tracking, Passenger and Fare Management, and En-route Transit Information. 69 II) Market Package APTS 1 Transit Vehicle Tracking A P T S 2 Transit Fixed-Route Operations APTS 3 Demand Response Transit APTS 4 Passenger and Fare Management APTS 5 Public Travel Security APTS 6 Transit Maintenance APTS 7 Multi-modal Coordination APTS 8 Enroute Transit Information APTS 9 Multi-Modal Connection Protection Table 5.8 - APTS Market Packages However, only two of these market packages have the potential to improve safety: • Public Travel Security '-This market package provides for the physical security of transit users using security systems both onboard (e.g. buses, trains) and in public areas (e.g. stops, park and ride lots, stations) deployed to perform surveillance and warn of potentially hazardous situations. Monitored information is relayed to transit and/or emergency centres for quick response during security incidents. This market package has the potential to reduce property damage and personal injury incidents through quick detection and response; it can be mapped to the "severity" metric, and the metrics associated with incident detection and response. • Transit Maintenance - This market package supports automatic maintenance scheduling and monitoring, and includes on-board condition sensors to monitor critical system status. With this market package, safety benefits can be realized by ensuring that unsafe vehicles that require maintenance are attended to prior to it to a 1 Although passenger security is not traditionally thought of as a topic related to traffic and road safety improvements, its benefits are "safety related", and therefore merit inclusion in this framework. 70 hazardous situation. This market package can be mapped to the mechanical failures metric. 5.3.4 Commercial Vehicle Operations The Canadian ITS Architecture includes twelve market packages under this category. These market packages cover a multiplicity of areas relating to the administration and management of commercial vehicle fleets and cargo, the clearance of commercial vehicles and freight at borders and other points of inspection, on-board safety monitoring, as well as hazardous material incident response. Their safety applications can be discussed in terms of two categories: regulatory applications, and vehicle/freight applications. Again, these categories have been defined for the purpose of this framework because the "Commercial Vehicle Operations" bundle of the Canadian ITS Architecture is too broad. The implications of these categories to the framework are discussed further in section 5.4). Commercial Vehicle Regulatory Applications - Market packages relating to this category are presented in Table 5.9. These market packages provide for ensuring that commercial vehicles meet the regulatory requirements, including safety, in the area they are in. These market packages are inter-related and focus on electronic clearance applications, whereby credentials information and Weigh-in-Motion (WEVI) information is used to pre-clear compliant vehicles so that efforts and resources can be focused on non-compliant vehicles. These applications contribute to safety by helping optimize the allocation of resources so that more non-compliant vehicles are caught. These market packages can be mapped to the "driver violations" metric. 71 ID Market Package CVO 3 Electronic Clearance CVO 4 Commercial Vehicle Administrative Processes CVO 5 International Border Crossing Clearance CVO 6 Weigh-in-Motion (WTM) CVO 7 Roadside CVO Safety Table 5.9 - CVO: Regulatory Market Packages in the Canadian ITS Architecture Commercial Vehicle and/or Freight Monitoring - Market packages relating to this category are presented in Table 5.10. These market packages provide for systems that can track and monitor the location and condition of commercial vehicles and/or their freight, such that appropriate actions can be taken during hazardous conditions. Similar to the transit applications, vehicle related market packages provide for automatic maintenance scheduling and monitoring, and include on-board condition sensors to monitor the condition of the vehicle. Safety benefits can be realized by warning drivers of mechanical failures associated with the vehicle, while providing information pertaining to the location of vehicles requiring assistance to a dispatch or emergency centre. These market packages can be mapped to the "mechanical failures" metric, and the incident detection and response metrics. With freight related market packages, safety benefits can be derived from accurate information on the location, content, and status of freight, such that appropriate response can be dispatched during incident conditions, such as those involving hazardous material. These market packages can be mapped to the metrics associated with incident detection and response, and mechanical failures. 72 ID Market Package C V O 1 Fleet Administration C V O 2 Freight Administration C V O 8 On-Board Safety Monitoring C V O 9 C V O Fleet Maintenance C V O 10 Hazardous Material Planning, and Incident Response C V O 11 Freight In-Transit Monitoring C V O 12 Freight Terminal Management Table 5.10 - CVO: Vehicle/Freight Market Packages 5.3.5 Emergency Management The Canadian ITS Architecture includes six market packages under this category. These market packages are presented in Table 5.11, and cover technology applications for managing and responding to emergencies. These market packages can be heavily tied into other market packages which provide the technologies and services required to detect emergency conditions (such as incident detection capabilities under the Highway Control market package); however their applications do "add" to the benefits of ITS, including safety benefits. For example, the safety benefits of an incident detection system are enhanced with the "emergency vehicle routing" market package. These market packages can be mapped to the metrics associated with incident response, as well as the accident/incident severity metric. ID Market Packages E M 1 Emergency Response Management E M 2 Emergency Vehicle Routing E M 3 Personal Security and M A Y D A Y Support E M 4 Disaster Command and Control E M 5 Disaster Information Dissemination Table 5.11 - Emergency Management Market Packages 73 5.3.6 Advanced Vehicle Safety Systems The Canadian ITS Architecture includes eleven market packages under this category. These market packages cover a number of areas related to vehicle and driver monitoring and information systems, collision warning systems, as well as collision avoidance systems. Their safety applications can be discussed in terms of these categories, which have been defined for the purpose of this framework because the "Automatic Vehicle Safety Systems" bundle of the Canadian ITS Architecture is too broad. The implications of these categories to the framework are discussed further in section 5.4). Monitoring System Applications - Market packages relating to this category are presented in Table 5.12. These market packages provide for improved safety by monitoring the vehicle, the driver, or enhancing the visual display of the surrounding environment. Specifically, the Vehicle Safety Monitoring market package can be mapped to the "mechanical failures" metric, while the Driver Safety Monitoring and Sensor-based Driving Safety Enhancement market packages can be mapped to the "driver errors" metric. ID Majk^P.ackage ;^.;.' AVSS 1 Vehicle Safety Monitoring A V S S 2 Driver Safety Monitoring AVSS 7 Sensor-based Driving Safety Enhancement Table 5.12 - AVSS: Monitoring System Market Packages Warning System Applications - Market packages relating to this category are presented in Table 5.13. These market packages provide improved safety by monitoring the vehicle surrounds and warning of potential collisions. As such, they have a direct relationship with crashes and can be mapped directly to the "crashes" metric. 74 ID Market Package AVSS 3 Longitudinal Warning Systems AVSS 4 Lateral Warning Systems AVSS 5 Intersection Collision Warning Table 5.13 - AVSS: Warning System Market Packages Collision Avoidance and Automated System Applications - Market packages relating to this category are presented in Table 5.14. These market packages provide improved safety by either temporarily or continuously taking control of the vehicle from the driver and avoiding potential crashes. Therefore, similar to the warning system applications category, they have a direct relationship with crashes and can be mapped directly to the crashes metric. ID Market Package AVSS 6 Pre-Collision Restraint Deployment AVSS 8 Longitudinal Collision Avoidance AVSS 9 Lateral Collision Avoidance AVSS 10 Intersection Collision Avoidance AVSS 11 Automated Vehicle Operation Table 5.14 - AVSS: Automated System Market Packages 5.3.7 Archived Data The Canadian ITS Architecture includes three market packages under this category. These market packages cover application areas related to the management, warehousing, and archiving of ITS related data. Market packages include Archived Data Mart, Archived Data Warehouse, and Archived Virtual Data Warehouse. These market packages can enhance the performance of other market packages, but do not have, on their own, a direct correlation to safety improvements. Therefore, they are not mapped to any evaluation metrics. 75 5.4 Framework Summary & Application Guidelines The previous sections have provided a detailed mapping of the market packages in the Canadian ITS Architecture to evaluation metrics proposed to measure ITS safety benefits, while taking into account "cause" and "effect" relationships among the metrics as a means of capturing the flow of those benefits. Tables 5.15A and 5.15B provide a summary of all the Market Packages in the Canadian ITS Architecture and how they map to the metrics. The process used to map the market packages in the Canadian ITS Architecture to the evaluation metrics has involved the categorization of similar market packages that can be evaluated using similar metrics. In some instances, these categories match the overall ITS "bundle" categories of the architecture, while in other instances new categories were defined. Table 5.16 provides a summary of these categories and their corresponding metrics (thus excluding those categories that were not mapped to any metrics). 76 CO 8 CO CP c o O O UJ • UJ UJ o UJ o LU LU CZ> CM u CS 1 < CU 3 M H co CD O o o (D m c to a: CD o g I ' c 'E T3 < "CD CD o 1 CD to c a in <a or c CD "O O CD to c 8j to . cu lor c CD I "9 o c c <D E s* CO c co t^ c CD CD l u l 0 o c CD 1 CD CD lO o> c to to o o 1_ CD "2 o m o > o CD •g to •o co o or a> to c o CL in CD or CD "O II C l c l CD I ID-c CD E to c to CD CO c to lo r s-1 c a> P>l UJ I I g CD > U c CD 21 CD E |UJ o Q. Q. > < a >-< c g co c E CD to to b CO E i o c to to l b to E tu c tl) E 0) o c CO CD . c E c LU o Q. a> CD M— Q Sa c O) to c l_ > U) CD Q or TJ c 0) o to to -ba •Col •JOS en 0. w o o ti 03 o !c tu > "O £ to E o ft) OJ « u 93 P* V U u cs 0J H D D es I PQ in r H v 3 CQ H 00 r -Canadian ITS Architecture Bundle Category Metrics Advanced Traveller Information Systems Traveller Information • Traffic Volumes • Congestion • Crashes Advanced Traffic Management Systems Traffic Management • Inadequate/Reduced Capacity • Congestion • Crashes Traffic Information & Warning • Traffic Volumes • Exposure to Hazards • Crashes Enforcement • Driver Violations • Crashes Commercial Vehicle Operations Monitoring Commercial Vehicles and/or Freight • Mechanical Failures • Incident Response • Crashes Commercial Vehicle Regulatory Applications • Driver Violations • Mechanical Failures • Crashes Emergency Management Emergency Management • Incident response • Severity • Crashes (secondary) Vehicle Safety & Control Systems Monitoring • Driver Error • Mechanical Failure • Crashes Warning • Driver Error • Crashes Control • Driver Error • Severity • Crashes Table 5.16 - Summary of Framework Categories to Metrics The above categorization is necessary because ITS deployments typically involve multiple market packages combined together. Therefore, the categorization allows similar functions to be aggregated for evaluation purposes. The categorization presented herein forms an important aspect of this evaluation framework by providing a bridge between the market packages in the Canadian ITS Architecture and the evaluation metrics. 79 Safety evaluation results derived by adopting this framework can be compiled and managed in a relational database that takes advantage of the structure described above. The notion of an "ITS Safety Benefits Database" can best be described by way of an example; in this regard, Table 5.17 presents a hypothetical example of how the benefits information can be related to each other in a database. < Category: Traffic Management ; Metric: Crashes Project ID Project Title Reported Value Confidence Level Dependence on Other Categories Surface Street Control Highway Control HOVLane Management Regional Traffic Control Electronic Toll Collection Reversible Lane Management Regional Parking Management Smart Work Zones 1 Name, Agency, Location -11% Low(1) Traveller Info. • </ </ 2 Name, Agency, Location -20% Medium (2) • </ 3 Name, Agency, Location -23% Medium (2) • </ 4 Name, Agency, Location -15% High (3) </ 5 Name, Agency, Location -45% Low(1) Enforcement • </ 6 Name, Agency, Location 8% Low(1) • 7 Name, Agency, Location -31% Low(1) Tally otMafkMPatklige'Occuroncos ' ' Weighted Average of Reported Values -19.1% 3 3 1 4 1 2 1 1 Table 5.17 - Potential Data Relationships for an ITS Safety Benefits Database The data structure represented in Table 5.17 would require one such table to exist for each category and metric combination (using Table 5.16 as a guide, this would result in 28 tables). The contents of each table can be summarized as follows: • Column 1 identifies each ITS project in the database using a unique identifier. • Column 2 identifies the project name, owning/operating agency, and location. • Column 3 lists the reported benefit results associated with different ITS project evaluations, as corresponding to the particular category and metric the table represents. 80 • Column 4 establishes a confidence level associated with the reported benefit result (column 3) associated with each project. The confidence level would be set depending on various factors such as evaluation method used, availability and quality of data, and the adequacy of the evaluation time periods. • Column 5 establishes whether the reported benefit value associated with a project may be dependent on other categories in this framework. For example, in some cases, an ITS project may include a broad range of market packages that would contribute to the same metric via different application categories. This is especially true for traffic management applications that are integrated with traveller information and/or traffic information and warning applications. For example, i f such a project was to yield a crash reduction of 20%, it would be unclear as to which proportion of the reduction was the result of the traffic management market packages and which proportion the result of the traffic information and warning market packages. Therefore, this "dependence" column provides a reference that a reported value is also reported under another category and is associated with other market packages.2 • Columns 6 and higher identify the market packages that are included in each project for which the evaluation results are attributed to. Within each table the list of market packages will be limited to those associated with the particular category and category/metric, as categorized under this framework. 2 Once such a database is populated with a sufficient sample of reported benefits, reported values from projects that do not have such dependencies can be averaged and used to determine the likely proportion of reported benefits that are associated with more than one category. 81 The very last row of the table provides an overall average of the reported values, using the assigned confidence levels for weighting the average. The last row also provides a frequency count of the market packages referenced in the individual results (thus highlighting the market packages making the largest contribution to the observed benefit results). The configuration illustrated in Table 5.17 and described above is intended to "summarize" the data relationships within the database; the actual design of the database would be based on a series of relational tables (whereby each evaluation result is an individual record with attributes such as the category or metric it belongs to, or its constituent market packages). Based on this type of a relational database structure, cross-tabulation queries can then be used to generate summary reports such as the example illustrated in Table 5.17. Furthermore, the database configuration will permit the generation of other summary reports by querying the specific feature of interest, such as "all results with a high confidence limit and including a particular market package" etc. 5.5 Framework Benefits The framework developed and described in the preceding sections attempts to provide improvements over existing evaluation practices related to measuring the safety benefits of ITS. These improvements relate to the addressing of some of the issues described in Chapter 4, by providing a basis for incorporating safety evaluations into an ITS project's planning process, and by providing a means of better reporting of safety benefits results. These benefits are described below. 1. The ITS safety evaluation framework developed herein addresses the fundamental issues associated with a lack of a consistent terminology (for attributing safety benefits to ITS) 82 by providing a correlation between the Canadian ITS Architecture market packages to the a set of evaluation metrics. This provides for a nationally consistent format for evaluating and documenting safety benefits of ITS, and can be expanded as new market packages are added to the architecture, or existing ones are modified. 2. This framework also addresses issues associated with a lack of, and deficiencies in, existing evaluation frameworks for evaluating ITS. On one hand, the framework developed herein is comprehensive in the sense that it encompasses all ITS application areas expected to improve safety; on the other hand, the framework is also focused to safety alone, without attempting to capturing all benefits of all ITS application areas. 3. The availability of a safety evaluation framework that is based on the Canadian ITS Architecture allows for the project planning and architecture definition phases of deployment to plan for, and make provisions for, subsequent safety evaluations. Specifically, when the system architecture for a particular ITS deployment has been developed with sufficient detail to identify its constituent market packages, the corresponding evaluation categories and metrics can be identified so that provisions for baseline data collection can take place. 4. Once the metrics have been identified and provisions for baseline data collection have been made, the requirements for the "post" data collection can be incorporated into the design of the system. Often, ITS deployments can be used to facilitate the post data collection effort (i.e. such as extracting crash data from the incident logs of an incident management system); therefore, system specifications related to data management and reporting can be geared towards generating data reports in a format that supports the evaluation task and is compatible with the before data samples. 83 5. B y p r o v i d i n g a causal inference between the metrics and thus establ ishing the f l o w o f benefits between the market packages and crash reduct ion, unrelated effects can be separated out w i t h more conf idence, result ing i n more re l iable benefits data. 6. I T S Safety evaluation results generated b y us ing this f r a m e w o r k can be c o m p i l e d and managed i n a database that maintains the correlat ion to the market packages i n the C a n a d i a n I T S Architecture . T h i s w i l l help ensure that as the extent o f deployments increase, associated benefits data can be aggregated and attributed to the appropriate I T S applicat ions. 84 6 C A S E S T U D Y A case study was undertaken as a means of further illustrating the issues associated with current ITS safety evaluation practices, while also highlighting the applicability and benefits of applying a more structure evaluation framework and using proper analytical methodologies. The case study illustrates the above points by way of the following: • Identification of the confounding factors that need to be taken into account for conducting "proper safety evaluations", and the manner in which they should be accounted for. • Undertaking of a "best possible safety evaluation" of an ITS project based on available data and project information. • Discussion of the applicability and benefits of the evaluation framework developed as part of this thesis. This discussion is presented in context of how the availability of such a framework could have helped in closing the gap between the "proper safety evaluation" desired and the "best possible safety evaluation" carried out. 6.1 Proper Safety Evaluations Conducting proper safety evaluation is not an easy task. Several factors can contribute to the difficulty of the evaluation: 1) The availability and quality of crash data. In most cases, crash data suffer from several problems related to the timeliness, quality and reliability. Here, timeliness refers to the 85 extent to which the data samples correspond to "before" and "after" the implementation of an improvement. Quality and reliability refer to the degree to which the data is accurate (i.e., in terms of location referencing, or descriptions, etc.). 2) The nature of crash data. Crashes are rare events, which affect the sample size needed for the evaluation (we may have to wait long time to obtain a statistically significant sample). Crashes are also random events and therefore the evaluation methodology should account for this randomness. 3) The need to control for confounding factors. A simple cause and effect relationship is rare in traffic safety. Usually, several factors operate simultaneously and therefore the effect of factors other than the treatment should be separated from the treatment effect. The evaluation process should ensure that a noted change in the number of crashes has been caused by the treatment evaluated and not by other "confounding" factors or causes. If other factors are allowed to contribute to the noted change then sound conclusions about the effect of the treatment cannot be drawn. 6.1.1 Confounding Factors Three main confounding factors are most relevant to traffic safety evaluation: history, maturation and regression artifacts. History refers to the possibility that factors other than the countermeasure being investigated caused all or part of the observed change in crashes. For example, i f the ITS improvement being evaluated involves the deployment of a Road and Weather Information System market package, then the evaluation should compare crash statistics during inclement weather 86 conditions, when the system is active. Therefore, the goal of the evaluation should be to separate the treatment effect from the effect of any other factor. Maturation refers to the effect of crash trends over time. For example, a comparison of crashes before and after the implementation of a specific ITS improvement may indicate a reduction that can be attributed to that improvement. However, it is possible that the reduction is part of a regional trend associated with improved driver education or demographics. Regression artifacts, or as more commonly known, regression to the mean (RTM) refers to the tendency of extreme events to be followed by less extreme events, even i f no change has occurred in the underlying mechanism which generates the process. In other words, "the highest will get lower and the lowest wil l get higher". Sites are usually selected for treatment because of a recorded high collision occurrence. This high occurrence may regress to the mean in the after-treatment period regardless of the treatment effect. This will lead to an overestimation of the treatment effect in reducing collisions. This R T M bias is considered the most important source of error in the evaluation of road safety programs. To illustrate the R T M effect, assume that the points in Figure 6.1 represent the number of collisions occurring at a certain site in each of the previous eight years. Although the average number of collisions is about seven, the individual frequencies range from 2 to 12. Let us assume that an ITS improvement was implemented in 1995 because of the high collision frequency (such as an automated enforcement system). Regardless of how effective the treatment, a subsequent analysis in 1996 would reveal a significant drop in collisions which can be attributed erroneously to the treatment. 87 14 Treatment Implemented —1 ^ 1 CD J3 0 1992 1993 1994 1995 1996 1997 1998 1999 Figure 6.1 - Example of RTM Effect 6.1.2 Techniques to Address Confounding Factors As noted above, history, maturation and regression artefacts represent three serious issues that can affect the quality and reliability of safety evaluations. The following subsections describe how some of these issues can be dealt with to ensure proper safety evaluations. 6.1.2.1 History and Maturation To account for the effect of history and maturation on the evaluation, it is usually proposed to use what is known as a "comparison group". In this method, a group of sites somewhat similar to the ones to be treated are selected and their collision occurrence is observed. By comparing the change in collisions in the comparison group to the change in collisions in the treated sites, the treatment effect can be calculated. 88 In context of the ITS safety evaluation framework developed as part of this thesis, the availability of clearly defined evaluation metrics will also help in dealing with history and maturation by allowing data collection requirements to be defined during project planning stages (through association with the project's constituent ITS architecture market packages). 6.1.2.2 Regression Artifacts To account for the R T M , the Empirical Bayes (EB) technique is usually used. Statistical methods can be classified into two main categories: Conventional methods and Bayesian methods. The two categories differ substantially. Bayesian methods are distinguished from conventional methods by the fact that any unknown parameter (such as the mean collision frequency at a site) is treated as a random variable having a specific probability distribution. Prior information about the parameter is used to establish its probability distribution (known as the prior distribution). Conventional methods, on the other hand, do not require any prior information about the unknown parameter. The main issue in Bayesian analysis is how to estimate the parameters of the prior distribution. In a pure Bayesian analysis, these parameters are usually assumed based on engineering judgment and past experience, while in the Empirical Bayes approach, the parameters are estimated using a sample of observations from a population of similar sites (usually called the reference group). A critical requirement that distinguishes the Empirical Bayes approach from conventional statistical methods is the use of a reference group. The reference group and the treatment group, collectively, should represent the entire population of treatment sites. 89 6.2 Case Study Project ( R E S C U Toronto, Ontario) The ITS project selected for this case study was the City of Toronto's Road Emergency Services Communications Unit (RESCU), which is a traffic management system incorporating real-time traffic and road monitoring capabilities, along with incident detection and management, and traffic information dissemination. The portion of the RESCU project selected for this case study is that of the Gardiner Expressway; RESCU itself encompasses a larger "corridor" traffic management system that extends the capabilities of the elevated Gardiner Expressway, to the arterial facility below it - Lake Shore Boulevard. The initial phase of RESCU was implemented in January of 1994. R E S C U is currently operated by the City of Toronto Works and Emergency Services Department. Figure 6.2 provides an overall map showing the location of the Gardiner Expressway within the City of Toronto. Figure 6.2 - Gardiner Expressway Context Map 90 RESCU includes a total of 37 CCTV cameras, a total of 121 loop detector stations: 4 Changeable Message Signs (CMS), 6 Rotating Drum Signs (RDS), and 2 Portable Changeable Message Signs (PCMS). The length of the R E S C U corridor is approximately 30km, out of which a 12 km stretch along the Gardiner Expressway has automatic incident detection capabilities. The Gardiner Expressway is classified as a 6 lane urban expressway. According to the City of Toronto (RESCU website), the purpose of RESCU is to significantly reduce the number and severity of vehicular collisions on the Toronto road system by providing early detection of incidents, and to improve the movement of people and goods by providing accurate and timely traveller information. Detailed traffic reports are generated by the R E S C U system for distribution by automated fax, remote computer dial-in (RTIS), direct telephone line and the Internet. 6.2.1 Available Crash and Traffic Volume Data Traffic incident and traffic volume data associated with the Gardiner Expressway portion of the R E S C U system were requested from the City of Toronto. Three basic data types/sources were made available by the City of Toronto for consideration: 1) Toronto Police motor vehicle collision data 2) R E S C U incident log data 3) Average Annual Daily Traffic (AADT) data Each of these data sources were associated with short-comings. The Police motor vehicle collision data is based on reports "filed" with the Police; the primary shortcoming with this type of data is the quality of the location referencing of the crashes, which is typically 91 approximated by the visual observation of attending officers using surrounding landmarks, or based on information filed by those involved in the crashes. The incident log data from the R E S C U system is very comprehensive, and includes all details associates with traffic incidents (such as vehicle breakdowns, crashes, etc.) occurring within the system's geographic coverage. However, this data is not archived in a database format. The details associated with incidents occurring on each calendar day is stored in separate text files. Due to disk storage requirements, these files are archived onto removable disk storage media. As a result, limited reporting functions exist once archiving has occurred (i.e. in terms of extracting data over a particular time period. Finally, since this data is associated with the R E S C U system itself, no comparable "before implementation" data would be available. For this reason, it was decided that the before and after comparisons of crash frequency undertaken as part of this case study would be based on the Police motor vehicle collision data - since both before and after samples would be of comparable quality, despite issues associated with geographic referencing etc. With respect to the traffic volume data, the City of Toronto made all available A A D T data associated with the Gardiner Expressway available. 6.2.1.1 Crash Data The City of Toronto's Traffic Data Centre & Safety Bureau provided a database of all collision reports filed by Toronto Police for a twelve year period between 1988 and 2000. 92 The manner in which the data was queried and coded had a number of deficiencies that required simplification of the database to ensure database integrity. Table 6.1 summarizes the deficiencies and the actions that were taken as part of the database "clean-up" process. Database Deficiency "Clean-up"' Action Each database record did not represent a single unique crash, rather each record represented each person involved in each crash. A combined query was made of all unique crash identifiers and the first person involved in each crash. The database was limited to Gardiner Expressway crashes by querying for all record and field combinations including various text referenced to "Gardiner". As a result, a portion of the crashes in the database related to crashes occurring along other streets (as the primary street) at or near the Gardiner Expressway (as the cross street). Also, crashes occurring on ramps on/off the Gardiner Expressway were included in the database, A l l records relating to the Gardiner express as a "cross street" were removed from the database, as well as all records related to ramps on/off of the Gardiner Expressway. A l l of the location referencing in the database was in "free-form" text, resulting in various references to the same primary or cross street (such as "Gardiner X " , "Gardiner Expressway", and "Gardiner X P W " e tc . ) . These inconsistencies were manually "cleaned-up" in the database. Cross-street location reference landmarks were not always relative to the nearest upstream interchange, and included over and underpasses, as well as other landmarks such as rivers etc. A l l such intermediate cross-streets were mapped to the nearest major cross-street/interchange, proportional to the sections for which A A D T data was available. Table 6.1 - Crash Database Deficiencies and Clean-up Procedures Crash data for a "comparison facility" to provide context of regional trends in crashes over the same time period was also obtained from the same source as above, and "cleaned" up using the same methodology tabulated above. The selected comparison facility was the Don Valley Parkway (also a 6 lane freeway) which runs in a north/south direction along the east side of the city of Toronto, intersecting the Gardiner Expressway at its southern most terminus. Figure 6.2, presented earlier, also illustrates the location of the Don Valley Parkway in context i f the City of Toronto and the Gardiner Expressway. 93 Figures 6.3 and 6.4 present the plots of the crash data compiled for the Gardiner Expressway and Don Valley Parkway, segregated in terms of total crashes, injury crashes, and rear-end crashes (these plots only represent crash frequency and do not reflect traffic exposure). Gardiner Expressway - Annual Crash Frequency CD ro 1200 1000 800 "g 600 o I 400 200 4 n B U M E3 Total • Se\ere • Rear End 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year Figure 6.3 - Gardiner Expressway Crash Frequency Don Valley Parkway - Annual Crash Frequency 1200 1000 800 600 400 -( 200 0 n i JUM a Total • Severe • Rear End 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year Figure 6.4 - Don Valley Parkway Crash Frequency 94 Figure 6.5 provides a comparative plot of the total crashes along the two facilities (again, it should be noted that this graph only represent crash frequency and does not reflect traffic exposure). The data suggests the following trends: • a general crash reduction trend around 1989 and 1990; • a period of fairly stable annual crash frequencies between 1991 and 1995; • a rising trend in crash frequency starting from 1996 onwards • a consistent differential in crash frequencies between the two facilities, with the Gardiner Expressway having a lower frequency of crashes. Crash Frequency Comparison 3 200 -^^^^^^^^^^^^^^^^^^^^^S^^B^^^^^g 0 i i i • i 1 1 1 1 1 1 1 1 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year Figure 6.5 - Comparative Plot of Crash Frequencies 6.2.1.2 Traffic Volume Data The City of Toronto's Traffic Data Centre & Safety Bureau also provided all available A A D T data for both the Gardiner Expressway and the Don Valley Parkway. The available 95 A A D T data was limited to the years 1989 to 1991 and 1998 to 2000. Figure 6.6 provides a comparative plot of the sectional A A D T data as averaged of the entire Gardiner Expressway and Don Valley Parkway corridors. Comparison of Daily Traffic Volumes 180000 160000 140000 120000 I— 100000 a ^ 80000 60000 40000 20000 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 • Gardiner Expressway • Don Valley Parkway Year Figure 6.6 - Gardiner Expressway Average AATDs The lack of available A A D T data associated with the years 1992 through to 1997 represents a significant deficiency in the data available for evaluation, and makes it difficult to establish any trends in the overall demand along the two corridors. Based on the limited data available, the following basic trends can be established: • the Gardiner Expressway experienced a rise in traffic volumes between 1989 and 1991, and a reduction in traffic volumes between 1998 and 2000. • The Don Valley Parkway had relatively consistent traffic volumes between 1989 and 1991, while experiencing a minor reduction in traffic volumes in 2000. 96 6.2.2 "Best Possible" Safety Evaluation The available data for evaluating the safety benefits of the RESCU project (as described above) does not satisfy all of the requirements for addressing the confounding factors discussed in Section 6.1 Proper Safety Evaluations. Specifically, the following should be noted: • History and Maturation: The large gap during which traffic volume data is not available (1992 to 1997) limits the opportunity for assessing implications of unrelated time-trend effects. At the same time however, the use of a comparison group (Don Valley Parkway) allows for some isolation of the treatment effects relative to unrelated effects. • R T M : The quantity and quality of the crash data is not sufficient for the application of the Empirical Bayes techniques for the analysis. Using the crash and volume data presented above, a rudimentary assessment of the safety benefits associated with the implementation of R E S C U (and its ITS subcomponents) can be carried using the following comparisons: • Simple before and after comparison of crash frequencies • Simple before and after comparison of crash rates • Simple before and after comparison of crash rates using a comparison group While the latter methodology is the "best possible" evaluation that can be carried out based on the available data, all three methods are presented in the subsequent subsections to illustrate the degree to which results can vary when poor methodologies are used. 97 6.2.3 Simple Before and After Comparison of Crash Frequencies The simple before and after analysis of crash frequencies provides the easiest method for measuring benefits after the introduction of an improvement or countermeasure, such as the deployment of an ITS application. In this method, a simple comparison between the number of crashes before and after treatment is undertaken. This method does not take into account traffic exposure; the main assumption of this method is that the number of collisions would not change had no treatment taken place. The statistical significance of any changes between the before and after periods can be tested using statistics such as the two-tailed T-test. Tables 6.2 to 6.4 provide details of this analysis for the individual segments of the Gardiner Expressway. Each table includes the before and after crash frequencies associated with each section of the Gardiner Expressway evaluated, along with an indication of the percent change, and significance using the two tailed T-test. It should be noted that sections 1 and 2 (Highway 427 and Royal York) were associated with potentially suspect data. It is suspected that this may be the result of poor geographical referencing in the collision reports - specifically associated with the consistency in which the western boundary of the Gardiner Expressway was distinguished from the Queen Elizabeth Parkway3 in the vicinity of Highway 427. While this data is included in the tables presented herein to illustrate the implications of poor data, the values have been excluded from the subsequent analysis and discussion. 3 The Queen Elizabeth Parkway represents the continuation of the Gardiner Expressway, west of Highway 427. Visual inspection of the crash data confirms various inconsistencies in the manner in which these two facilities were distinguished from each other in the vicinity of Highway 427. 98 Evaluation Sections Before After % 2-Tailed Significant Crash Freq. Crash Freq. Change TTest ? 1 Highway 427 5 376 7420% -19.007 Yes 2 Royal York 22 184 736% -11.287 Yes 3 Humber River 615 333 -46% 9.159 Yes 4 British Columbia 948 820 -14% 3.044 Yes 5 Spadina Avenue 545 657 21% -3.230 Yes 6 Sherbourne Street 198 145 -27% 2.862 Yes Average of All Sections 389 419 8% -1.067 No Average of Sections 3 to 6 577 489 -15% 2.689 Yes Table 6.2 - Comparison of Total Crash Frequencies Before After % 2-Tailed Significant cvciiuciiion oeciions Crash Freq. Crash Freq. Change TTest • ? 1 Highway 427 3 155 5067% -12.092 Yes 2 Royal York 10 106 960% -8.913 Yes 3 Humber River 381 222 -42% 6.475 Yes 4 British Columbia 594 578 -3% 0.467 No 5 Spadina Avenue 297 428 44% -4.865 Yes 6 Sherbourne Street 63 52 -17% 1.026 No Average of All Sections 225 257 14% -1.466 No Average of Sections 3 to 6 334 320 -4% 0.538 No Table 6.3 - Comparison of Rear-End Crash Frequencies Evaluation Sections Before After % 2-Tailed Significant Crash Freq. Crash Freq. Change TTest ? 1 Highway 427 1 115 11400% -10.585 Yes 2 Royal York 3 65 2067% -7.519 Yes 3 Humber River 204 110 -46% 5.305 Yes 4 British Columbia 309 242 -22% 2.854 Yes 5 Spadina Avenue 185 206 11% -1.062 No 6 Sherbourne Street 64 42 -34% 2.137 Yes Average of All Sections 128 130 2% -0.145 No Average of Sections 3 to 6 191 150 -21% 2.195 Yes Table 6.4 - Comparison of Severe Crash Frequencies Figure 6.7 provides a summary of the percent reduction in crash frequency along the Gardiner Expressway when comparing the before and after periods 99 Percent Reduction in Crash Frequency Severe Crashes 21% ' Rear End Crashes 4 % Total Crashes 15%, 0% 5% 10% 15% 20% 25% 30% Figure 6.7 - Percent Reduction in Crash Frequency The results suggest that the section of the Gardiner Expressway bounded by Humber River and Sherbourne Street experienced a 15% reduction in crash frequencies, when comparing the periods of 1989 to 1991 (before period) with 1998 to 2000 (after period). Analyzing subsets of this data suggests a 4% reduction in rear-end only crash frequencies, and 21% reduction in severe only crash frequencies. As stated earlier however, use of crash frequencies alone is not the preferred methodology since unrelated effects are not separated. 6.2.4 Simple Before and After Comparison of Crash Rates The above method can be enhanced to account for changes in exposure (traffic volumes between the before and after periods) through the calculation of crash rates. The calculation of crash rates for highway sections is illustrated in Equation 1 below. Crash Rate = Number of _ Crashes [1] Million Vehicle Kilometers 100 Where Million Vehicle Kilometers AADT x 365 x No.Years x Section _length 106 [2] Use of the crash rates for before and after comparisons helps to separate unrelated effects, associated with changes in traffic volumes over the evaluation time period, from the analysis. Using the available A A D T and crash data, crash rates where calculated for the Gardiner Expressway. Tables 6.5 to 6.7 provide details of this analysis by the individual segments of the Gardiner Expressway. For the same reasons outlined in section 6.3.1, data associated with sections 1 and 2 of the Gardiner Expressway (at Highway 427 and Royal York) are included in these tables, but excluded from subsequent analysis and discussion. ' Evaluation Sect ions Distance (km) • ' Before , After <*•<•:•< • - r ••%<--,-t AADT Crash Freq. Crash Rate AADT Crash Freq: Crash Rate Change-1 Highway 427 4.00 213023 5 0.005 219023 376 0.392 7214% 2 Royal York 2.63 199186 22 0.038 207909 184 0.308 701 % 3 Humber River 3.50 189881 615 0.845 197646 333 0.440 -48% 4 British Columbia 3.63 160710 948 1.486 168813 820 1.224 -18% 5 Spadina Avenue 2.25 134965 545 1.639 137309 657 1.942 18% 6 Sherbourne Street 1.75 101143 198 1.022 105374 145 0.718 -30% Average of All Sections 17.75 166485 2333 0.721 172679 2515 0.749 4% Average of Sections 3 to 6 11.13 146675 2306 1.291 152285 1955 1.054 -18% Table 6.5 - Comparison of Total Crash Rates Evaluation Sect ions "*'„ Distance (km) Before . ; . - . . . - . f ^ f t e rAv t ' . " ., ., V ' ; % " ? : AADT Crash Freq. Crash Rate AADT Crash Freq. Crash Rate Change' ' 1 Highway 427 4.00 213023 3 0.003 219023 155 0.162 4925% 2 Royal York 2.63 199186 10 0.017 207909 106 0.177 916% 3 Humber River 3.50 189881 381 0.524 197646 222 0.293 -44% 4 British Columbia 3.63 160710 594 0.931 168813 578 0.863 -7% 5 Spadina Avenue 2.25 134965 297 0.893 137309 428 1.265 42% 6 Sherbourne Street 1.75 101143 63 0.325 105374 52 0.258 -21% Average of All Sections 17.75 166485 1348 0.417 172679 1541 0.459 10% Average of Sections 3 to 6 11.13 146675 1335 0.747 152285 1280 0.690 -8% Table 6.6 - Comparison of Rear-End Crash Rates 101 Evaluation Sections Distance (km) Before After % AADT Crash Freq. Crash Rate AADT Crash Freq. Crash Rate Change 1 Highway 427 4.00 213023 1 0.001 219023 115 0.120 11085% 2 Royal York 2.63 199186 3 0.005 207909 65 0.109 1976% 3 Humber River 3.50 189881 204 0.280 197646 110 0.145 -48% 4 British Columbia 3.63 160710 309 0.484 168813 242 0.361 -25% 5 Spadina Avenue 2.25 134965 185 0.556 137309 206 0.609 9% 6 Sherbourne Street 1.75 101143 64 0.330 105374 42 0.208 -37% Average of All Sections 17.75 166485 766 0.237 172679 780 0.232 -2% Average of Sections 3 to 6 11.13 146675 762 0.426 152285 600 0.323 -24% Table 6.7 - Comparison of Severe Crash Rates Figure 6.8 provides a summary of the percent reduction in crash rates along the Gardiner Expressway when comparing the before and after periods. Percent Reduction in Crash Rate Severe Crashes Rear End Crashes Total Crashes 0% 5% 10% 15% 20% 25% 30% Figure 6.8 - Percent Reduction in Crash Frequency The results suggest that the section of the Gardiner Expressway bounded by Humber River and Sherbourne Street experienced an 18% reduction in crash rates, when comparing the periods of 1989 to 1991 (before period) with 1998 to 2000 (after period). Analyzing subsets of this data suggests an 8% reduction in rear-end only crash rates, and 24% reduction in severe only crash rates. 102 As with the previous method, these results are deficient in the sense that they do not account for the R T M phenomenon. 6.2.5 Simple Before and After with a Comparison Group While the use of crash rates improves on the use of crash frequencies by reflecting effects associated with changes in traffic volumes, other unrelated effects (such as a rising trend in crashes due to changes in the demographics of drivers) can still impact the reliability of before and after crash rate comparisons. To separate the "treatment effect" (i.e. changes in crash rates occurring as a result of the improvement being evaluated) from other unrelated effects, a "comparison group" or a "control group" is used. With this method, before and after crash rates are calculated for another highway somewhat similar to the one being evaluated. By comparing the changes in crash rates in the comparison group to the change in crash rates in the treated facility, the treatment effect can be calculated. Using this method, a statistic is calculated to account for the effects of factors other than the treatments or improvements being evaluated. This statistic is referred to as the Odds Ratio (O.R.) which represents the change of crashes in the comparison group to the change of crashes in the treatment group. O.R. = — [3] B/D where: A = Comparison Group - Before Crash Rate B = Treatment Group - Before Crash Rate C = Comparison Group - After Crash Rate 103 D = Treatment Group - After Crash Rate The treatment effect is then represented as: Treatment Effect = \-O.R. [4] As noted earlier in section 6.1.1, the Don Valley Parkway was selected as a comparison facility for the Gardiner Expressway. Tables 6.8, 6.9, and 6.10 present the calculation of the O.R. and Treatment Effect for total, rear-end only, and severe only crashes respectively. It should be noted that with this methodology, when highway sections are being evaluated, the before and after values for the comparison group are averaged over the entire comparison facility (i.e. to calculate values A and C in Equation 3), and are compared against sectional values for the facility begin evaluated (i.e. various values of B and D in Equation 3). Similar to Gardiner Expressway, crash data associated with sections 5 and 6 of the Don Valley Parkway (at Bayview Avenue and Dundas Street East respectively) were also found to be suspect. Again it is suspected that this may be the result of poor geographical referencing in the collision reports - specifically associated with the consistency in which crashes in the vicinity of the Bayview Avenue off-ramp were referenced and coded. 104 2 2 o _ S E Q (A C o o © in c: g *3 CO _3 TO > UJ a), CO c CO o Q> o c-' re. , in a CO c o *3 ••o a CO - f t ' . 3 o CD c ' o <n *c ' to Q . 'E o o ce CU JS Vi CQ o H W S3 <U £ 03 cu s-H 00 H o O co ro Ol in CM N" og CM CD re 01 in in in (A ro O o o o m co re CO CM O CO 2 a u c re § E |<fl ~ l Q V) c a u <D CO c o re > UJ CM CO ' I IX m m co CO CO o CO 10 c p -•3 0) 2 CD a> cn c re s: X) o _ re.il (0 i in c .2 u a> in o c ,o <n *c re a E o o oo o co 00 I CO m M CO d co | LU CD c CD > < CD O c CD i_ CO JS U a O a W i-es cu w +^  a <u E CJ OJ i-H I ON vo 3 « V) C •2 co CM-CO c o l « C4> CO O I <D I 0)1 s 1 2 o o , g E 10 c •:2 o cu co ' c o re _3 re > UJ CD 0). c ro o 5? 2 2 CO o O o CO a 3 o O "c o (0 re a. E o o cu JS in C3 i -V £ 1 a O CU a; V5 o U. +^  a cu s cu H I o 1—I CU S3 H Figure 6.9 illustrates the reduction in crash rates when corrected using crash rates associated with a comparison group. The results suggest that the section of the Gardiner Expressway bounded by Humber River and Sherbourne Street experienced a 38% reduction in crash rates, when comparing the periods of 1989 to 1991 (before period) with 1998 to 2000 (after period). Analyzing subsets of this data suggests a 30% reduction in rear-end only crash rates, and 43% reduction in severe only crash rates. These results are improved over the results from the previous methods because they are relative to "what would have happened had no improvements been implemented" by taking into account the crash trends along a comparison facility. In this case the comparison group experienced increases in crash rates of 32%, 36%, and 58% for total, severe, and rear-end crashes (as illustrated in Tables 6.8, 6.9, and 6.10). Again, as noted earlier, R T M effects were not considered in this analysis due to the quantity and quality of available data. Percent Reduction in Crash Rates 0% 10% 20% 30% 40% 50% Figure 6.9 - Percent Changes in Crash Rates Using a Comparison Group 108 6.3 Summary of Analysis Results The analysis presented in the previous section represents the "best possible" safety evaluation of the R E S C U system based on available data. Although the analysis results suggest a potential for safety benefits attributed to the introduction of RESCU, they also highlight a low level of confidence in the magnitude of the results due to limitations in the quality and quantity of data. Furthermore, by presenting the variations in measured benefits as a function of the analysis methodology, the results infer a low confidence level in the reported results from other similar project evaluations. These limitations are discussed further in the following sections. 6.3.1 Data Deficiencies The most fundamental deficiency in the available crash data was the location referencing of the crashes. The location referencing of the available crash database was based on a "Street Name 1" and "Street Name 2" data-field configuration, whereby the former identifies the facility on which the crash occurred, while the latter identifies the closest cross-street west or south of the crash. However, theses database fields were defined as "free-form" text fields whereby the street names are entered at the discretion of the person who filed the report or entered the data. This results in poor quality data because multiple references to the same street can exist in the database. For example, as part of the data clean-up process of the database, a query made of all the unique names in the "Street Name 1" field of the database resulted in 143 unique references. In a properly structured database (with error checking features), there should have been a single reference to "Gardiner Expressway" with all other related information in the other fields (such as type of facility, direction etc); however, the 109 143 unique references included various permutations to the basic text "Gardiner". This issue extended to the referencing of "Street Name 2", whereby multiple references existed for various cross-streets etc. The second most important deficiency in the data available for this evaluation was the lack of A A D T data for the years 1992 to 1997. As a result of this, the before period was limited to 1989 to 1991, while the after period was limited to 1998 to 2000. Although the implementation of R E S C U was initiated in 1994 with subsequent phases and enhancements in the following years, the wide gap between the before and after periods of the evaluation results in the introduction of other unrelated factors that could have impacted safety, both positively, and negatively. 6.3.2 Impacts of Methodology Aside from the data deficiencies identified above, the before and after evaluation carried out also provides a relative comparison of how simple variations in the evaluation methodology can affect the estimate of benefits. Figure 6.10 provides a summary of the results by evaluation methodology and crash type. Comparing the results, a wide disparity can be observed in the estimated crash reduction factors. Specifically, the following is observed: • Total crash reduction estimates range between 15 to 38% • Rear-end only crash estimates range between 4% to 30% • Severe only crash reduction estimates range between 21% to 43% 110 45% 40% a 35% +-a 3 30% "3 K 25% si 20% 15% 10% 5% 0% Percent Reduction in Crashes by Analysis Methodology Total Crashes 4% Rear End Crashes Severe Crashes • Crash Rate w/ Comparison Group • Crash Rates • Crash Frequency Figure 6.10 Variations in Crash Reduction Estimates Due to Methodology The magnitude of disparity among the results is consistent with that of the previously reported results in the literature (presented in chapter 3.0 of this thesis). This further highlights the importance of using appropriate methodologies for carrying out safety evaluations. Specifically, utilising the correct statistical distributions to represent underlying crash occurrence patterns, and taking into account the three most typical statistical adjustments (i.e. for time trends, traffic volume, and RTM) can affect results significantly. As illustrated in this analysis, not only can these adjustments change the results by several percentage points, but they can completely reverse conclusions drawn from the data. This issue weakens the reliability of much of the ITS safety benefits reported to date, since the vast majority of the references which cite before/after crash statistics have been based on simple before/after analyses; few make explicit reference to adjusting for traffic volume, or 111 reference to a comparison group to adjust for time trends. No references were found to incorporate adjustments for selection bias and R T M effects. 6.4 Framework Application Notwithstanding the data and methodology deficiencies discussed above, the need for an evaluation framework is clearly demonstrated when one also considers that the disparate benefit estimates can be attributed to various categorizations / definitions of the RESCU project, i.e. traffic management system, incident management system, traveller information system. The evaluation framework developed as part of this thesis could have helped in the safety evaluation of the R E S C U project in a number of ways. These are discussed in the following sections. 6.4.1 Framework Application & Benefits During Project Planning Although neither the US or Canadian ITS Architectures were existing at the time RESCU was planned, the availability of this framework (and thus the existence of the architectures) would have been beneficial in subsequent safety evaluations of RESCU. Specifically, the constituent market packages and corresponding categories and evaluation metrics would have been identified early on. Table 6.11 presents the Canadian ITS Architecture market packages that are incorporated in the RESCU system, along with their corresponding category and metrics. 112 Market Packages Category Metrics • Broadcast Traveller Information • Interactive Traveller Information Traveller Information • Traffic Volumes • Congestion • Crashes • Highway Control • Traffic Information Dissemination Traffic Management • Inadequate/Reduced Capacity <» Congestion <» Crashes Traffic Information & Warning o Traffic Volumes o Exposure to Hazards o Crashes Table 6.11 - Market Packages Incorporated in R E S C U As illustrated in table 6.11, the metrics that could be used for evaluating the safety benefits of the R E S C U system include traffic volumes, congestion, inadequate/reduced capacity, and crashes. Using these metrics, a comprehensive baseline data collection program could have been planned, and could have included the following: • AADTs along the major sections within the study corridor, along with peak periods hourly volume variations. • Peak period level of service statistics (as a measure of congestion) and variations using the peak period hourly volume variations. • Incident duration data for the purpose of generating statistics associated with the percentage of time available capacity is reduced due to incidents. • Crash data with location referencing that can be easily correlated with the A A D T sectional data. 113 • Supporting and similar data from a comparison facility. 6.4.2 Framework Application & Benefits During Project Design The availability of the metrics and collection of the baseline data during the project planning stages permits the project's design phase to incorporate provisions necessary for the "post" data collection. Specifically, the system specifications associated with data management and reporting functions could have included the following functions: • Ability to generate AADTs (using the vehicle detector station data) corresponding to the sections for which baseline data was obtained. This simple reporting function would facilitate ongoing analyses requiring A A D T data without having to allocate time and resources to manually compute AADTs using data that does not match the baseline referencing system. • Ability to use the incident log database to generate statistics associated with the percentage of time lanes are blocked due to incidents. • Ability to use the incident log database to generate crash data according to various user-definable query requests (such as section, time of day, crash type, and crash severity), supported by the ability to use the query data to generate crash rates through correlations with the A A T D data. These simple types of reporting functions would also be useful in maintaining a hardcopy log of key statistical reports prior to the archiving of the historical data, after which the data required to generate such reports would no be easily accessible. 114 6.4.3 Framework Application & Benefits During Evaluation and Reporting In addition to facilitating the process required to identify evaluation metrics, and collecting before and post implementation data, this framework could have also assisted in the manner in which the results from the evaluation are reported. The current evaluation has only yielded an estimated reduction in crash rates (using data with a low confidence level due to the wide gap between the before and after periods). The overall reduction estimated is 38%, however, it is difficult to ascertain which proportion of this is the result of the traffic management category of market packages versus the traffic information and warning category of market packages. 115 7 S U M M A R Y , C O N C L U S I O N S , A N D R E C O M M E N D A T I O N S 7.1 Potential for ITS to Improve Safety The potential for ITS to improve the safety of our transportation system is indirectly demonstrated by the continually increasing investments in ITS by public and private sector owners, operators, and maintainers of our transportation systems. According to ITS Canada, the annual world market for ITS is estimated to be C$25 billion in 2001, C$60 billion by 2006, and C$90 billion by 2011. Furthermore, these investments are made under the auspices that they will lead to the achievement of a number of goals, of which safety is most commonly referenced as the primary goal, and followed by others relating to efficiency, economic productivity, and the environment. Finally, the safety benefits of ITS are inherently recognized and appreciated by transportation safety professionals, since the improved ability to manage congestion, reduce incident response and duration times, and warn users of hazards are all associated with improved safety. Nevertheless, despite the investments, goals, and expectations, there is a deficiency in the extent to which ITS safety benefits are derived from actual, quantitative, evaluations. 7.2 Work Done to Date & Associated Issues A review of the currently available literature on the safety benefits of ITS suggests reported benefits suffer either in quantity and/or quality, due to the following issues: 116 • Inconsistent Terminology - There has been a lack of consistent terminology associated with the ITS classifications used for attributing safety benefits. This has undermined available benefits results because of over reporting (i.e. where the same observed crash reduction estimate has been associated with multiple ITS categories such as A T M S and ATIS). • Relatively Low Extent of Deployment - There is a general lack of available safety benefit results associated with a number of ITS application areas due to limited (but increasingly growing) deployments (such as C V O or in-vehicle systems). • Lack of Evaluation Framework - There is a large disparity in the quality of available ITS safety benefit evaluation results due to a lack of an evaluation framework that ensures a consistent means of undertaking evaluations and reporting results with associated confidence levels. 7.3 Developed Evaluation Framework and its Benefits In light of these issues, and the ongoing need in the ITS community to better demonstrate the safety benefits of ITS, a framework has been developed for evaluating the safety benefits of ITS. Through a number of unique features, this framework addresses the terminology issue, and provides guidance for incorporating more structured evaluation methodologies. These unique features can be characterized as follows: • A set of evaluation metrics have been identified for measuring the safety benefits of all ITS application areas. Furthermore, these metrics have been correlated with each other to demonstrate the flow of benefits between the metrics (for example, reducing incident response and duration times help restore capacity, which helps reduce 117 congestion, which contributes to lower crash frequencies). By taking into account the flow of benefits between the metrics, safety evaluations can take into account the contributing factors to observed reductions in crash rates, while also being able to separate unrelated effects. • The market packages of the Canadian ITS Architecture have been classified into logical application groupings that contribute to similar safety benefits. These market package groupings have been mapped to the evaluation metrics defined as part of the framework to provide a comprehensive linkage between the application areas in the Canadian ITS Architecture and the evaluation metrics. This link not only addresses the terminology issues associated with previous evaluations, but also provides a means of incorporating provisions required for undertaking ITS safety evaluation studies in the a project's planning and ITS architecture definition phase. Combined, these unique features of the evaluation framework provide an opportunity for setting up an ITS Safety Benefits Database that takes advantage of a structured relationship between the Canadian ITS Architecture market packages and the evaluation metrics (including their relationships with each other), thus ensuring a structured means of compiling reported ITS safety benefit results. The need for, and benefits, of this framework have been indirectly demonstrated by undertaking a case study which illustrates the disadvantages of "not having had the framework". The project selected for the case study was the R E S C U traffic management system in Toronto. Using limited A A D T data and poor quality crash data, a before and after comparison of crashes was undertaken. The results highlighted the disparity that can exist in 118 the estimated crash reduction benefits as a result of poor data and variations in the evaluation methodology. For example, comparing crash data before and after implementation of R E S C U showed the estimated reductions to be 15% i f crash frequency was considered, 18% if crash rates were considered, and an astounding 38% i f crash rates were used in conjunction with a comparison facility. The issue of proper methodology and data are interrelated in the sense that the application of a good methodology requires good quality data. Finally, without a consistent terminology, evaluation results (regardless of the quality of methodology and data) can be "lost" by being attributed to various and inconsistent combinations of ITS classifications. 7.4 Further Research The framework approach developed as part of this thesis also opens the door for additional research activities aimed at improving the ongoing goal of capturing the benefits of ITS. These activities can include: • Development of a supporting framework for assigning confidence values to the estimated safety benefits. The assignment of confidence values can be based on whether and how a number of issues were dealt with in an evaluation study, such as quality of data, use of a comparison group, statistical reliability, etc. • Development and refinement of the metrics associated with C V O and AVCSS market packages. Both of these areas have the potential to contribute significantly to safety; however, both suffer from a low level of deployment relative to other application areas. As deployment levels increase, and more experience is gained in the planning, 119 design and operation of such systems, new or modified metrics can be defined to better estimate associated safety benefits. Development of a structured database to support this framework by setting up the relationships between the Canadian ITS market packages and the metrics, as presented in this thesis, while providing templates for the data entry, cross-tabulation queries, and reporting of the data. Use of the existing ITS safety benefits references to populate the proposed database. This may require liaison with the original authors to establish confidence levels associated with the methodologies and data used. Development of a similar framework for other major ITS goals (i.e., efficiency, mobility, environment, and economic productivity). For example, for each goal, associated metrics and "cause" and "effect" relationships can be defined and mapped to the Canadian ITS Architecture market packages. Each of these individual frameworks could be linked together (via their common "cause" and "effect" metrics to provide an overall framework for evaluating all ITS benefits. This overall framework could also be complemented by a structured database for reported benefit results; and, could be integrated with the Canadian ITS Architecture documentation and training programs to ensure that the evaluation of ITS benefits becomes an integral part of ITS planning and design. 120 R E F E R E N C E S Allsopp, R. (1998). "Safety Evaluation of Ramp Metering in Glasgow Using the Asset Image Processing System", ITS World Congress (5th) Conference Proceedings, Seoul, Korea. B C MoT. (1997). 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"Development of Canadian Architecture for Intelligent Transportation Systems", Final Report - Volume B, The Canadian National Architecture Framework for ITS, Transport Canada, Ottawa, Canada. Tribbett, L., McGowen, P., Mounce, J. (2000). " A n Evaluation of a Dynamic Curve Warning Systems in the Sacramento River Canyon: Final Report", Western Transportation Institute. Montana State University. TTI. (1998). "ITS Benefits: Review of Evaluation Methods and Reported Benefits", Texas Transportation Institute, FHWA/TX-99/1790-1, Austin, Texas. TxDoT. (2002). "About TransGuide", Internet Web Site: www, transguide. dot, state, tx. us/docs/atms info, html, Texas Department of Transportation, San Antonio, Texas. US DoT. (1999). "Executive Summaries, National ITS Architecture Documentation", U.S. Department of Transportation, Federal Highway Administration, Washington D.C. US DoT. (2000). 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"Nation Intelligent Transportation System Program Plan Five Year Horizon", U.S. Department of Transportation, Intelligent Transportation Systems Joint Program Office, Washington D.C. 123 A P P E N D I X A - M A R K E T P A C K A G E S IN T H E C A N A D I A N ITS A R C H I T E C T U R E AD1 Archived Data Mart AD2 Archived Data Warehouse AD3 Archived Data Virtual Warehouse APTS1 Transit Vehicle Tracking APTS2 Transit Fixed-Route Operations APTS3 Demand Responsive Transit APTS4 Passenger and Fare Management APTS5 Public Travel Security APTS6 Transit Maintenance APTS7 Multi-Modal Co-ordination APTS8 En-Route Transit Information APTS9 Multi-Modal Connection Protection ATIS1 Broadcast Traveller Information ATIS2 Interactive Traveller Information ATIS3 Autonomous Route Guidance ATIS4 Dynamic Route Guidance ATIS 5 ISP-Based Route Guidance ATIS 6 Traffic Estimation and Prediction ATIS7 Traveller Services Payment and Reservation ATIS 8 Ride Matching ATIS9 In-Vehicle Signing ATMS1 Traffic Network Flow Monitoring ATMS2 Probe-Based Flow Monitoring ATMS3 Surface Street Control ATMS4 Highway Control ATMS5 H O V Lane Management ATMS6 Traffic Information Dissemination ATMS7 Regional Traffic Control A T M S 8 Incident Risk Prediction System ATMS9 Predictive Demand Management A T M S 10 Electronic Toll Collection A T M S 11 Emissions Management A T M S 12 Virtual T M C and Vehicle-Based Sensing A T M S 13 Basic At-Grade Crossing Control A T M S 14 Advanced At-Grade Crossing A T M S 15 Modal Operations Co-ordination A T M S 16 Electronic Parking Payment and Parking Facility Management A T M S 17 Reversible Lane Management A T M S 18 Road Weather Information System A T M S 19 Regional Parking Management ATMS20 Roadway Environmental Sensing ATMS21 Roadway and Weather Data Fusion ATMS22 Environmental Information Dissemination ATMS23 Roadway Micro-Prediction 124 ATMS24 Maintenance Fleet Management ATMS25 Smart Work Zones ATMS26 Dynamic Roadway Warning ATMS27 Variable Speed Limit and Enforcement ATMS28 Signal Enforcement ATMS29 Mixed Use Warning Systems ATMS30 Automated Non-Vehicular Road User Protection AVSS1 Vehicle Safety Monitoring AVSS02 Driver Safety Monitoring AVSS03 Longitudinal Warning Systems AVSS04 Lateral Warning Systems AVSS05 Intersection Collision Warning AVSS06 Pre-Collision Restraint Deployment AVSS07 Sensor-Based Driving Safety Enhancement AVSS08 Longitudinal Collision Avoidance AVSS09 Lateral Collision Avoidance AVSS 10 Intersection Collision Avoidance AVSS 11 Automated Vehicle Operation CVO01 Fleet Administration CVO02 Freight Administration CVO03 Electronic Clearance CVO04 Commercial Vehicle Administrative Processes CVO05 International Border Crossing Clearance CVO06 Weigh-In-Motion (WIM) CVO07 Roadside CVO Safety CVO08 On-Board Safety Monitoring CVO09 C V O Fleet Maintenance C V O 10 Hazardous Material Planning and Incident Response C V O 11 Freight In-Transit Monitoring C V O 12 Freight Terminal Management E M I Emergency Response Management EM2 Emergency Vehicle Routing EM3 Personal Security and M A Y D A Y Support EM4 Disaster Command and Control EM5 Disaster Information Dissemination 125 

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