What would you think if you heard that something was causing an increase in the number of fatal and injury traffic collisions and, at the same time, diminishing our air quality, creating less social interaction among community members, significantly reducing levels of physical activity and increasing the prevalence of obesity among the population?

If you think this sounds ominous, you would be right-these are some of the consequences of recent trends in land use, traffic, and public transportation planning that, while intended to provide improved quality of life and increased mobility to their inhabitants, leave residential areas increasingly isolated and often serviced by higher-speed and less-safe arterial roads. When combined with fears that unaccompanied child pedestrians are vulnerable to stranger abduction, more and more people, especially in North America, are choosing to drive, and to drive their children to school, rather than choosing other forms of transportation, such as walking or riding their bicycle (SRTS Task Force, 2008).

This is an example of behavioural adaptation-behaviours which may occur following the introduction of changes to the road-vehicle-user system and which were not intended by the initiators of the change (OECD, 1990, p. 23).