Role of information on probability of traffic conflict on the onset of yellow

This paper examines the effect of information provided to drivers through advance warning flashers (AWFs) on driver’s probability of conflict at the onset of yellow at a high-speed intersection. AWFs are specifically designed to minimize the number of vehicles trapped in their respective dilemma zones at the onset of yellow. A probit modeling technique was used to establish dilemma zone boundaries. Based on the dilemma zone boundaries probability of a perceived conflict curves was computed and compared against actual conflicts observed at each of the studied intersections. The comparison between the actual and theoretical probability of conflict curves generated a better understanding of the risk associated with providing drivers with information prior to the onset of yellow through the use of advance warning flashers (AWFs). Results found that providing drivers with information in advance of the intersection using AWFs can potentially cause increased risk in RLRs and/or severe decelerations. Thus, caution should be used by engineers before providing drivers with information at a high speed intersection.