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Integrated behavioral and economic framework for improving dilemma zone protection systems
Theses and Dissertations Available from ProQuest
  • Anuj Sharma, Purdue University

There are approximately 68 million instances per day of signal change to yellow phase at high speed isolated intersections where an erroneous decision to stop or go can often lead to a crash. Dilemma zone protection systems are typically used to control these intersections to ensure safe and efficient movement of vehicles. However, the traditional dilemma zone protection systems show deterioration in performance during medium to heavy volume condition, thus jeopardizing both safety and efficiency of the intersection. ^ This dissertation seeks to unify the concepts of existing dilemma zone protection system (green extension and green termination) and traffic conflict theory using enhanced radar-based sensors to provide safe and efficient operation at rural signalized intersection. The proposed approach is also devised to operate with the boundaries of existing sensor and hardware technology thus avoiding the need of extensive hardware configuration changes. It borrows concept of trade-off between safety and efficiency from green termination systems and recasts it in the economic framework. The proposed approach considers the problem in the terms of marginal costs and benefits of extending the main-street green to ensure the safe passage of approach traffic at the cost of delay incurred to the waiting queue. The economic framework is so designed that it can be used by both green extension or green termination system and the system benefits would enhance based on the accuracy of the vehicle detection and tracking. ^ The cost function uses monetary value of delay faced by the queue due to the extension of main-street green. Traditional surrogate measure of safety, dilemma zone, only marks the region of risk but does not quantify the level of risk which is essential to use the economic framework. So, an improved surrogate measure of safety, dilemma hazard function, is developed by expanding the existing measure of safety and using the concept of traffic conflict. The probability of having a severe traffic conflict defines the dilemma hazard function, which is used to quantify the benefits of safety. A behavioral model is then used to develop dilemma hazard function in conjunction with critical acceleration and deceleration threshold. ^ Key points of significance to the current practice observed during the course of the research are: (i) Economic framework provides an adaptive approach to ensure optimal level of protection to the high speed vehicles based on the traffic volumes on the opposing movements whereas, tradition dilemma zone protection system is all or nothing approach in terms of level of protection and also non-adaptive to the volume of opposing movements. (ii) Observation made by comparing the existing dilemma zone boundaries and dilemma hazard function showed that the current approach are provide protection in the region where a single vehicle have a low risk of crash and are leaving the area where vehicle has a high risk of crash. (iii) Adaptive wide area sensor technology promise significant potential over the existing sensor technology for improving operation at high speed isolated intersection.^

Subject Area
Engineering, Civil
Date of Award
Degree Name
Citation Information
Anuj Sharma. "Integrated behavioral and economic framework for improving dilemma zone protection systems" (2008) p. 1 - 132
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