An Optimized Advance Detector Configuration for Option Zone Protection at High Speed Signalized Intersections

47 Advance detection and green extension schemes are widely applied in practice as a typical 48 solution to the safety issues associated with the intersection dilemma zone (DZ) problem. Most 49 existing detector configurations were either developed based on the traditional Type I DZ model 50 in which some critical contributing factors were assumed static, or based on generic Type II DZ. 51 A comparison analysis based on field-observed trajectory data showed that the option zone 52 model estimated the location of dilemma zone most accurately among all available dilemma 53 zone models. The authors’ recent research on the quantitative modeling of option zone’s 54 contributing factors made it possible to accurately identify the option zone locations. That lays 55 out a solid foundation for developing an option zone-based detection scheme in order to achieve 56 the most effective and efficient dilemma zone protection. This paper presents an alternative 57 advance detector configuration for option zone protection via optimization trials within a 58 calibrated VISSIM simulation model. The optimization objective was to minimize the combined 59 cost of dilemma hazard (safety) and delay (mobility). Dilemma Conflict Potential, a 60 comprehensive dilemma hazard model was used to quantitatively measure the safety 61 performance, as a replacement for the traditional measure of “number of vehicles in dilemma 62 zone”. The optimal configuration was evaluated and validated via its comparison with four 63 widely-applied detector configurations in the nation. The results revealed the superiority of the 64 developed optimal detector configuration in terms of the best safety performance and the least 65 combined cost of dilemma hazard and delay among all configurations. 66 67 68