Citation

Lieberman EB, Woo JL. Transp. Res. Rec. 1976; 596: 16-21.

Copyright

(Copyright © 1976, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper describes a new signal timing optimization program, SIGOP II. The optimization procedure consists of two major components: a flow model and an optimization methodology. The objective function of system disutility is expressed directly in terms of vehicle delay, stops, and excess queue length (a congestion deterrent). The flow model computes these components of disutility in the course of the optimization procedure. The optimization procedure uses the method of successive approximations within the framework of a dynamic programming methodology. Gradient techniques are applied to explore a response surface representing system disutility and to locate the minimum value. Associated with this minimum value of disutility is the optimal signal setting sought by the optimization procedure. The platoon structure of traffic and its interaction with the control at the intersection are described. Continuity of flow is preserved from one link to the next. Turning movements, lane channelization, and multiphase control are explicity treated. Practical considerations such as signal split constraints, platoon dispersion, and the effect of short-term fluctuations in volume are included. This program, coded in FORTRAN, is currently being refined and extended. A comparison of SIGOP I and SIGOP II is given.