UBC Theses and Dissertations
Evaluating hazardous roadside locations using the Roadside-Hazard-Simulation-Model Version 9 (1992) De Leur, Paul
Vehicles that "run-off-the-road" and crash into a hazardous roadside are a significant problem, accounting for 14.3 percent of all highway accidents in the Province of British Columbia. The computer tool developed in this project is designed to help evaluate hazardous roadside locations and evaluate various improvement alternatives proposed to reduce the level of hazard. The hazard level at any location may be reduced by: flattening the embankment slope, installing a roadside barrier, removing hazardous objects, or any combination of the three. The evaluation tool, a computer simulation model, identifies the "best" solution from a set of improvement alternatives simulated for a hazardous location. The computer simulation model is called the Roadside-Hazard-Simulation-Model Version 9.0 (RHSM.V9), and was developed after a great deal of effort was devoted to simply modifying and revising one of the previous versions of the model (RHSM.V5 (1978), RHSM.6-2 (1982), or RHSM.V7 (1986)). The new model was developed using the important components of the previous versions and anticipating the additional factors needed in the new model. Making the new-version user-friendly and flexible was important since previous versions were difficult to use, unforgiving in nature, and consequently rarely used. There are a number of objectives which RHSM.V9 satisfies. First, the model simulates an errant vehicle's trajectory upon leaving the roadway. Secondly, the model is capable of accurately simulating the hazards that exist in the roadside. Third, the model simulates the roadway conditions, as well as the errant vehicle's characteristics. The fourth objective, which is dependant upon the first three objectives, determines the consequence of the vehicle leaving the roadway and entering a hazardous roadside. Finally, the model does an economic evaluation of the improvement alternatives proposed for the location and identifies the best solution for the hazardous roadside location. The model's performance was illustrated by performing numerous program runs and then evaluating the results produced by the model. The evaluation included a results comparison with previous versions of the model, a results evaluation for various hazardous embankment slopes and roadside objects, and a sensitivity analysis of the operational parameters and economic factors used in the model. Also included in this evaluation were four typical examples from "real-life" applications. After preliminary testing of the model, the results, and the trends in the results, appear to be valid. The general conclusion of this thesis is that RHSM.V9 can be used to improve the engineering analysis process in evaluating hazardous roadside locations. The program is a user-friendly computer tool to assist highway safety professionals in making a decision regarding the implementation of roadside safety improvement alternatives. The final decision must be made in conjunction with sound engineering judgement. Further research and updating may be easily incorporated since the program has been structured such that as better calibration information becomes available, it can be immediately and easily included in the new model.
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