CANADIAN JOURNAL OF CIVIL ENGINEERING, cilt.40, sa.3, ss.274-284, 2013 (SCI-Expanded)
Delay, which can be defined as the difference between interrupted and uninterrupted travel times through an intersection, is one of the most important performance indicators for intersection analysis. It can arise from several types of conditions like intersection geometry, drivers' perceptions, traffic characteristics etc. Minimum delay, which can be stated as the delay faced by a minor stream driver when the minor stream flow is nearly zero, is a base delay measure of an unsignalized intersection that should be analyzed in depth. In this study, an appropriate minimum delay equation is derived for single-lane traffic circles in Izmir, Turkey. For this purpose, observations are made at seven approaches of five single-lane traffic circles. Many types of model structures like exponential, power, best subsets regression etc. are constituted and compared with the existing approaches. Results have shown that, geometry of a traffic circle has an important effect on minimum delay and should be considered in analysis. In the study, the effect of entering vehicles from the minor approach is also investigated. A new delay model that depends on the entry flow is also suggested.