An illustration of the "dilemma zone" studied by Dr. Gang-Len Chang



Dr. Gang-Len Chang

University of Maryland



Project Report: 

 NTC 2014 Information Form_Principal Investigator_Gang-Len Chang_September 2014.pdf

 NTC 2015 Information Form_Principal Investigator_Gang-Len Chang_March 2015.pdf

 NTC2014-SU-R-04 Gang-Len Chang.pdf

Subject Area: 

Applied Research




When the traffic signal at a high speed intersection turns to yellow, motorists are faced with the critical decision to either stop or proceed through the intersection. In some instances, motorists find themselves in the dilemma zone, a region on the intersection approach where motorists can neither safely stop nor pass through an intersection before the minor road traffic is released. Recognizing that the dilemma zone is a serious safety issue at high speed intersections, many dilemma zone mitigation strategies have been developed and tested. One such strategy that has shown potential is a detection, control, and warning system (DCWS) (Zimmerman et al., 2012). However, those warning strategies may offer insufficient protection of dilemma zones at very high speed intersections (Chang et al., 2013) and field tests of such systems are yet to be conducted. With that in mind, the purpose of this research is to design, implement, and evaluate a dilemma zone protection system at a high speed rural intersection.