A computer program, OSCADY, has been developed to model capacities, queues and delays at isolated traffic signal junctions. The program includes recently derived empirical formulae for saturation flow calculations, routines to optimise signal settings and time-dependent equations for queue and delay prediction. The user inputs include geometric characteristics of the junction, signal timing arrangements, and demand flow information. OSCADY is intended to model peak period operation, although longer periods can be considered. The program can model most staging arrangements at three- or four-arm junctions. OSCADY can either implement supplied timings or be used to calculate suitable ones. Queues and delays are calculated for each of a succession of short time segments (usually 10 or 15 minutes) within the modelled period. Both existing or proposed layouts can be assessed, and the effects of possible modifications examined. The program can be used on most types of computers (including micro-computers), and both batch and interactive versions are available.
Samenvatting