The Generalized Combination Method for Area Traffic Control

Abstract

A procedure is described for determining optimal signal settings in a network including cycle time, splits of green time and ffsets. A number of cycle times are scanned in the process. For each cycle, splits are determined locally at each intersection according to proportions of conflicting traffic loads, and offsets are optimized by the Generalized Combination Method. Total cost for travelling through the signal-controlled intersections in the network is evaluated as the sum of two components: deterministic and stochastic. The deterministic component is a function of the offsets throughout the network and generally increases with cycle length. The stochastic component is dependent on the expected overflow queue on each link nd decreases with cycle length. Optimal settings are determined as an e(ui ibriumi point of minimum total costs resulting from the combined effect of the two components.