Network Analysis under Variable Demand Conditions - The SIDRA Method

Abstract

The SIDRA method for Variable Demand Analysis for intersections and networks is a new feature introduced in SIDRA INTERSECTION Version 9.1. The Variable Demand Model is useful for multi-period analysis of persistent congestion. The model uses the Initial Queued Demand in estimating delays, queue lengths and stop rates when sequential flow periods are analysed in cases of congested conditions. Initial Queued Demand is the Residual Queued Demand left over from the previous flow period when a lane is oversaturated. The presentation includes an introduction to the key aspects of the SIDRA Variable Demand Model, a basic Network example to show the complexity added to the Variable Demand Model for Networks due to Capacity Constraint requirements, and an analysis of the congested conditions for the Westbound traffic during the am peak period in the Alexandra Parade corridor in Melbourne, Australia. The analysis applied the Variable Demand Model to four 15-min flow intervals for the 7.30 - 8.30 am flow period, and estimated the long queue extending from Alexandra Parade to the Eastern Freeway successfully. The presentation also includes a short summary of the main features of Network modelling in SIDRA INTERSECTION.