Peak Travel Study – About as Useful as Peak Oil Studies

It’s important to have some understanding of the resource availability for things like water, oil, food and other critical items.  But in some cases, like that of ‘peak oil’ – where maximum extraction has been achieved and cannot be maintained – there’s the problem of a moving target.  Too many variables and assumptions come into play about determining existing and future supplies and capacity to make the numbers very reliable.

I was intrigued by a study that focused on the idea of an extraction peak in demand, rather than supply.  WIRED’s Autopia blog has a summary, and the full study is available (subscription or purchase required) in Transport Reviews (H/T Miller-McCune).

If you’ve clicked through those links, there’s at least one glaring issue with the study, especially if you’re looking at this concerned about emissions.  The focus of the study is on the industrial world, where the conclusions are based on decreases in the energy intensity of vehicles on the road and in a leveling off of passenger travel. As the U.S. and China are the top emitting countries in the world, the omission of the non-industrialized world presents at best a limited picture of ‘peak travel’ that reinforces the characterization of this study as suggestive, not conclusive.

As I can’t access the actual study, I can’t be certain that the non-industrial world isn’t effectively considered, but based on the press coverage it is not a particular focus.  The Miller-McCune piece at least covers the non-industrialized world angle with one of the study’s authors, and in doing so, highlights another variable that would appear to be important – travel infrastructure.  With several major cities around the world effectively choked with traffic, we have infrastructure that is often close to maximum carrying capacity, if not exceeding it.  How can we be certain that this ‘peak travel’ is not a function of demand for travel, but in the ability to travel?

I think it’s fine to have this study out there and publicized.  I just think it needs to be taken with the proper amount of consideration.  Acknowledge the limitations, and by no means advocate for particular policy choices based on it.  It’s too small of a picture on the relevant phenomena to be the basis for a change.