Author : Ali Ewadh, Hussein
journal of kerbala university,
Volume 3, Issue 3, Pages 130-140
Traffic accident data are the principal tool for identifying degree of safety at traffic system. In situation of no reliable accident record, traffic conflict technique TCT is a suitable alternative aid. This paper aims at studying the traffic safety at three-leg signalized intersections using TCT.
Three different sites of three-leg signalized intersections are selected according to specified criteria. The data concerning; traffic volume, traffic conflict, are collected using video camera. Spot speed and some of the geometric characteristics (lane width, median width, and availability and length of auxiliary left lane), are determined and measured due to observation at site.
A developed model shows that, an extra increase of traffic conflicts can be represented by negative exponential trend in relation with approach traffic volume. That negative exponential model shows a better explanation rather than linear model. On the other hand, developed models are introduced to indicate the traffic conflict rate in relation with some geometric characteristics. Further, a statistical analysis of extracted data of previous works in sites of four-leg signalized intersections reveals that no significant dependency of traffic conflict occurrence, in relation with approach traffic volume, with the type of signalized intersection (three or four legs). In addition, it is found that, linear relation explains increasing variation (97.8%) of total hourly traffic conflict in relation with total stopped delay time. This may reveals that the potential conflict increases when drivers argue from unacceptable delay introduced due to the traffic operation at the intersection.