Reliability Modeling and Simulation of Signalized Intersections

With the stochastic characteristics analysis of traffic flow at a signalized intersection, the definition of phase clearance reliability is introduced to optimize and evaluate the status of traffic flow. Based on the probability theory and the Gaussian elimination method, the quantitative relationship is explored among phase clearance reliability, cycle length and green time. Then, a calculation formula of the phase clearance reliability is deduced from the stochastic of traffic flow that obeys the normal distribution and negative exponential distribution. A simulation example of a two-phase signalized intersection is presented at the final section. The results indicate that the cycle length usually increases with the variance of arrival rate, and more green time is needed for the phase with larger variance of arrival rate. The randomness of arrival rate has a significant effect on cycle length and green time, and the phase clearance reliability can be used to design and evaluate the traffic signal settings.