With South East Queensland’s population growing by more than 1000 per week there is a large associated increase of vehicles on Brisbane roads. Brisbane is expected to experience gridlock situations by 2011 unless significant changes are made to our roadways or methods of transport. Intelligent Transport Systems (ITS) are one of the emerging approaches to reducing traffic congestion. As there is a limit to how much additional space we can devote to roadways, it is vital that our current roadway network is managed efficiently to its full potential.
The effectiveness of ITS applications can be evaluated either using field studies or laboratory simulations. Field studies are costly and time consuming to undertake. Traffic simulation studies inside a controlled laboratory environment provide a better approach without the need to disrupt traffic conditions in the field.
This thesis explores the application of microscopic traffic simulation to evaluate the existing toll operations on the Gateway Bridge. The Bridge is vital to the South East Queensland region as it provides access to Brisbane Airport and the Port of Brisbane. Current traffic volumes are considered to be approaching the capacity of the Bridge under its current toll plaza configuration. ITS technologies, in particular electronic toll (E Toll) payment systems, where toll payments are made electronically alleviating the need to stop in order to pay toll, is a promising approach to better manage the demand on the toll facilities and reduce congestion on the Bridge. This thesis will quantify the effectiveness of such systems and investigate the possibility of a full electronic toll collection system being able to meet the projected 2011 demands.
Using AIMSUN, a microscopic simulation package, this thesis developed a model of the Gateway Bridge for the purpose of evaluating toll collection performance. The base model (2005) was calibrated using field data and was found to replicate field conditions with an acceptable degree of confidence. Once calibrated and validated, the model was used to evaluate the toll operations under 2011 conditions.
The results showed that if no alterations were made to the current facility average section times would double by 2011, emphasising the need for an improved method of toll collection. It was also found that if E toll were to be introduced the average section time would be four times less those found in the 2011 model. These results display the effectiveness of E Toll and the potential benefits that could be found by its implementation. Through this study it was also found that 2011 traffic flows can be accommodated by providing just four E Toll lanes, potentially alleviating the need to add road capacity by duplicating the Bridge facility. The thesis documents the assumptions and limitations of the approach used and provides guidance for further research in this field.