A Modified Webster Model for a Useful Traffic Signal Timing Plan

Today, many methods are known in the world for calculating fixed-time signaling plans. The effective operation of fixed-time signalized intersection is achieved through plans calculated on the basis of peak-hour field data so that the plans respond to both free traffic conditions and congested ones. One of the most frequently used methods is the well-known Webster's formula, which is based on the optimal calculation of the cycle duration that promises the minimum drivers experienced delays. Since the original Webster formula also has its own flaws regarding the overestimation of the cycle time in cases where the degree of saturation rate corresponds to congestion conditions, in this paper a modified model is pro-posed. In order to obtain reasonable cycle length for every range of saturation rates the modified model is based on optimized timing plan driven by Synchro/Sim Traffic soft-ware which is mostly compatible with Highway Capacity Manual (HCM 2010).