Advance detection and green extension schemes are widely applied in practice as a typicalsolution to the safety issues associated with the intersection dilemma zone (DZ) problem. Mostexisting detector configurations were either developed based on the traditional Type I DZ modelin which some critical contributing factors were assumed static, or based on generic Type II DZ.A comparison analysis based on field-observed trajectory data showed that the option zonemodel estimated the location of dilemma zone most accurately among all available dilemmazone models. The authors’ recent research on the quantitative modeling of option zone’scontributing factors made it possible to accurately identify the option zone locations. That laysout a solid foundation for developing an option zone-based detection scheme in order to achievethe most effective and efficient dilemma zone protection. This paper presents an alternativeadvance detector configuration for option zone protection via optimization trials within acalibrated VISSIM simulation model. The optimization objective was to minimize the combinedcost of dilemma hazard (safety) and delay (mobility). Dilemma Conflict Potential, acomprehensive dilemma hazard model was used to quantitatively measure the safetyperformance, as a replacement for the traditional measure of “number of vehicles in dilemmazone”. The optimal configuration was evaluated and validated via its comparison with fourwidely-applied detector configurations in the nation. The results revealed the superiority of thedeveloped optimal detector configuration in terms of the best safety performance and the leastcombined cost of dilemma hazard and delay among all configurations.
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