Traffic Impact Assessment of Land Use Proposals: Fifty Years of Australian Experience

Draft traffic impact assessment (TIA) guidelines for various landuses in general, and for high traffic generating buildings in particular, were published in Iran in the middle of 2016. In formulating that report the Traffic Committee of the Iranian Building Engineering Order reviewed international experience, including that of Australia. Traffic impact assessment started in Australia in the 1960s when the traffic police exercised much authority in trying to prevent land-use developments from taking place abutting main roads. Concepts derived from queuing theory (Blunden, 1966) – the application of the mean service time to establish maximum traffic generation rates for a proposed development and the absorption capacity of a priority traffic stream – found their way into traffic engineering practice to provide a rational basis for assessing development applications. As experience accumulated the guidelines became refined and a second edition of Austroads’ traffic impact assessment was released in 2016. This paper explains those developments, outlines what documentation is expected from a developer, describes the traffic models available to the consultants working for the developer, and notes the importance of developer contributions should the proposed development require changes to the surrounding transport network. To illustrate the process in a more practical manner, a simple case study of a school expansion is provided to illustrate the principles of TIA and to point to the onus on all developers to manage travel demands to achieve more sustainable outcomes from urban development. The references cited at the end of this paper provide material for more detailed study.