Gap Acceptance, and Traffic Safety Analysis On U-Turn Median OpeningsOf Arterial Roads


ABSTRACTIn this study, eight locations on U-turn median openings in Duhok City were investigated about gaps or lags of traffic opposing and delaying traffic turning left. Other data was collected from the scene like conflicts with turning traffic, travel speed, and volumes of opposing and parallel flow. Accident frequency experienced near U-turn openings location for three years (2005-2007) was collected too.Analysis of data using statistical methods show different empirical models correlating independent variables like , gap length travel speed , traffic volume , approach width , conflict rate…etc. with dependent variables like , delay time , accident rate , and percentage of drivers accepting or rejecting gaps . Average lag obtained to control safety of studied locations was 3.5 sec.Key Word: Gap Acceptance, Duhok