Long-term trends in modal share for urban passenger travel

The Bureau of Transport and Regional Economics (BTRE) has recently conducted a study of the avoidable social costs of congestion in Australia. Congestion imposes significant costs on society with interruptions to urban traffic flow lengthening average journey times, making trip travel times more variable, and making vehicle engine operation less efficient. The latter leads not only to higher rates of fuel consumption, than would otherwise have occurred, but also to poorer urban air quality (with vehicles under congested conditions typically emitting far higher rates of noxious pollutants than under more freely flowing conditions, resulting in even higher health costs to the community). As part of the investigation of congestion occurrence, long-term trends in traffic within the Australian capital cities were analyzed. These trend analyses form the basis of the findings discussed in this paper.