Recently (April 2001) I attended a planning workshop which explored a “functional” way of looking at metropolitan transport systems. This involved looking at the main travel purposes rather than the more conventional approach of looking at modal subsystems – cars, trains, buses.

Starting point

Sydney is fortunate in being relatively rich in personal travel data from a rolling Household Travel Survey program. Based on this source, the six personal travel functions identified for the workshop, and the proportion of weekday metropolitan trips they accounted for in Sydney in 1999, were as follows.

A seventh function was added, "move goods", to reflect urban freight movement.

Reflection

I like this approach, which emphasizes the why rather than the how of transport. Many issues flow from it, for instance it becomes clear that weekend travel is not just a lower-volume version of a weekday and calls for attention in its own right if it is not to be surrendered to car dependency. However it does tend to reflect data availability. We know a lot (in Sydney) about personal travel and are able to identify six distinct functions. We have little data about commercial travel and hence lump it all together into one function, "move goods".

A little thought suggests that there is at least as much variety in commercial movement (loosely defined here as anything not undertaken for personal reasons) as in personal movement.

My preferred categorization would also recognize the existence of services as well as goods as generators of movement. In fact the dreaded acronym GST could be pressed into use: Goods, Services, Travel.

On this basis, one of the six functions above ("perform work") becomes a service trip rather than a personal trip, variety within the "move goods" function appears and further types of trip in the "services" sector also appear. Similarly, five functions may appear too many for an initial cut at personal transport.

The absence of data collected on these lines does not invalidate the approach ! Indeed one of the main reasons often put forward for the lack of substantial planning for commercial functions, as was the case with trips other than journey-to-work in the past, is that we do not know enough about them.

My view of the main functional components of movement, with this broader approach, are set out in the table below. I note that, increasingly, some of these functions can be met by use of IT services, for those with access to them, rather than by physical movement.