Editor:

The ASE Vision Committee in the coming months may discuss not just the airport itself but also ground transportation from the airport to Aspen and Snowmass. In those discussions, the bottleneck at the Entrance to Aspen (ETA) may once again raise its ugly head. Some will be of the opinion at the outset that the induced demand theory dictates that any expansion of the roadway to relieve ETA congestion would be futile, as the Aspen Institute’s Upper Valley Mobility Report assumed in 2017 when it expressly didn’t study the question.

But there is a problem with the induced demand concept: it can lead policy makers to miss the opportunity to thoughtfully discuss and analyze whether a given traffic congestion problem might be solved by an increase in capacity. The original proponents of the induced demand concept, Hansen and Huang of UC Berkeley, warned against this: “one can certainly envision situations where adding lane-miles, by removing some traffic bottleneck, results in . . . better traffic conditions... Consequently, the normative implications of our results are tentative at best. Definite evaluations of the costs and benefits of road expansion must be made at a more disaggregate level... Simple models ... cannot supplant the detailed analyses needed to evaluate specific projects. It should not be assumed that the aggregate elasticities obtained in our analysis apply equally to every urban region, let alone to any particular project.”

For induced demand to occur, demand must be elastic. Underpinning the belief that four-laning or realigning the ETA would not relieve congestion, or that it would increase congestion in Aspen, is the assumption that ETA demand is elastic, i.e., that if, people didn’t have to waste half an hour getting into and out of Aspen most days, more would come, more often. 

That assumption is just a fear. No expert has opined that, if the ETA bottleneck were widened or realigned, Aspen’s traffic congestion floodgates would open. No “granular” discussion of that question has taken place, at least not in a public forum. In their upcoming discussion of ground transportation to and from the airport, that would be a good place for the ASE Vision Committee to start.

Barry Vaughan

El Jebel