Most capital cities in Australia and New Zealand are experiencing some levels of congestion on their freeway networks. Sydney, Melbourne and Brisbane are experiencing congestion between three to eight hours per day. This paper reviews the literature on the characterisation of freeway flow breakdowns. Freeway flow breakdown is a complex phenomenon. There have been useful researches in the development of models for the analysis and better understanding of flow breakdowns. However, these models all have their own limitations. Freeway data at a detailed level with small time slices and high density of detector stations is becoming more available in recent years. It is now possible to investigate the time and space features of flow breakdowns in spatio-temporal diagrams such as speed contours. An empirical spatio-temporal approach is recommended for congested freeway flow analysis. This paper also describes the tools developed to analysis the breakdown process and some initial results based on the analysis of freeway data from a 17 km segment of the Monash Freeway in Melbourne. (a) For the covering entry of this conference, please see ITRD abstract no. E217099.
Abstract