Bus Following Model: A Case Study in Edinburgh

A number of car following models have been developed and calibrated for the purpose of understanding and simulating the behaviour of driving under various traffic and transportation management systems. Such studies are useful for safety impact studies, network analysis and capacity analysis. However bus following is a special behaviour, which impacts on other traffic especially in the absence of dedicated bus lanes. This paper reports on a study in the City of Edinburgh which was undertaken to investigate and understand the behaviour of buses in the city. A commuter bus equipped with a data logging device was followed by an instrumented vehicle to collect data to study bus following behaviour. A model of distance difference as a function of the acceleration/deceleration, speed and speed difference has been developed for bus following behaviour. The GHR model was used to investigate and calibrate the parameters of the model of the car following a bus. The study findings show that the speed and acceleration of the following vehicle are influenced by the leading commuter bus in both acceleration and deceleration regimes. The results also show that a car following a bus behaves differently to a car following a car. This is because of the limited visibility, huge delays for buses on the corridor and the different driving characteristics of the bus with respect to the car.