Optimizing Offsets in Signalized Traffic Networks: A Case Study

We evaluate the performance of an algorithm, developed by [1], that formulates offset optimization for a traffic network with arbitrary topology as a quadratically constrained quadratic program. The algorithm adjusts the offset values of traffic signals in urban networks to reduce delay and the number of stops. The performance of two real-world networks using the offsets obtained by the algorithm and those obtained using Synchro, a popular software package for traffic signal timing, is compared via simulation using the VISSIM microscopic traffic simulator. The offsets obtained by the algorithm reduce the average number of stops and total delay that vehicles experience along the major routes in both networks and under several traffic profiles as compared with offsets obtained from Synchro. In addition, the original model assumed infinite storage capacity for links, we eliminate this assumption to make the model more realistic. In this paper we show theoretical work of adding storage capacity constrains to the original optimization problem, along with an example of the results from modified version of the algorithm.