@prefix vivo: . @prefix edm: . @prefix ns0: . @prefix dcterms: . @prefix dc: . @prefix skos: . vivo:departmentOrSchool "Applied Science, Faculty of"@en, "Civil Engineering, Department of"@en ; edm:dataProvider "DSpace"@en ; ns0:degreeCampus "UBCV"@en ; dcterms:creator "Vahidi, Homayoun"@en ; dcterms:issued "2009-08-14T23:12:51Z"@en, "2002"@en ; vivo:relatedDegree "Master of Applied Science - MASc"@en ; ns0:degreeGrantor "University of British Columbia"@en ; dcterms:description """The benefits of ITS are indirectly represented by the annual world market for ITS, which according to ITS Canada will be CDN $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 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."""@en ; edm:aggregatedCHO "https://circle.library.ubc.ca/rest/handle/2429/12224?expand=metadata"@en ; dcterms:extent "8261892 bytes"@en ; dc:format "application/pdf"@en ; skos:note "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 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 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. • 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 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 < CD O c CD i_ CO JS U a O a W i-es cu w +^ a CO O I 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. 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(2000). \"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 "@en ; edm:hasType "Thesis/Dissertation"@en ; vivo:dateIssued "2002-05"@en ; edm:isShownAt "10.14288/1.0063660"@en ; dcterms:language "eng"@en ; ns0:degreeDiscipline "Civil Engineering"@en ; edm:provider "Vancouver : University of British Columbia Library"@en ; dcterms:publisher "University of British Columbia"@en ; dcterms:rights "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en ; ns0:scholarLevel "Graduate"@en ; dcterms:title "A framework for evaluating the safety benefits of intelligent transportation systems"@en ; dcterms:type "Text"@en ; ns0:identifierURI "http://hdl.handle.net/2429/12224"@en .