Calibrating microscopic simulation models

Abstract

Paper presented at the 26th Annual Southern African Transport Conference 9 - 12 July 2007 "The challenges of implementing policy?", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT:South African government, public and private organisations are investigating the potential benefits of the application of Intelligent Transport Systems (ITS) in South Africa. It has become clear that microscopic simulation models are required to estimate the impact of ITS measures. Nevertheless, no specific South African microscopic simulation models have been developed and the question needs to be asked if it is appropriate to use developed world models in the South African context? An extensive analysis of existing models has lead to the application of the microscopic simulation model Paramics. Micro-simulation models allow assigning and simulating the movement of individual vehicles, on the roads and intersections within a local area network in order to design and evaluate traffic management and control strategies. The Paramics model is calibrated on UK driving behaviour. The driver behaviour and driving conditions in South Africa can be found to be very different to those of the developed world. It was found that no research has been carried out in South Africa with regards to driving behaviour. Moreover, traffic flow data that can assist during the calibration process, is often not available. This paper describes the investigation of available models, as well as the calibration process undertaken. Moreover, the importance of the calibration process is discussed, comparing results of calculations using default settings and calibrated parameter settings. In this study two corridors (the Ben Schoeman Highway (BSH) and the N2 near Cape Town) were investigated. It appears that calibrated parameter settings for both corridors are significantly different from the default setting!