Month April 2009

Chris Bradford over at Austin Contrarian has been making some solid points in favor of congestion pricing. (here, here, here and here)  Chris’s core argument in favor of congestion tolling is that: congestion pricing does more than relieve congestion.  Congestion pricing tells us when a road needs more capacity.  Additional capacity costs money, and drivers are willing to pay only so much for it.  That “so much” is exactly equal to the price they are willing to pay to avoid congestion. The idea that toll profits send a signal to road operators to produce additional capacity is often neglected in discussions of the benefits of congestion pricing.  Without pricing, the only signal is the manifestation of congestion itself.  This is problematic, as the only solution is to build more roads when congestion is observed.  Actually if done right, years before congestion occurs with the help of foresight and luck on the part of transportation planners and agencies.  This problem feeds the dangerous new highway –> sprawl –> congestion –> highway expansion –> sprawl, etc., etc. positive feedback loop.  This feedback loop is quite a powerful mechanism that helps drive the unhealthy types of sprawl. Chris is on the right track, but sets a sub-ideal objective (in my opinion) when he says: The optimal congestion toll should be set just high enough to achieve free-flow (45 mph) traffic. Since the goal should not only be to avoid congestion, but to get the highest number of commuters through the system as possible, I would restate that as: The optimal congestion toll should be set at exactly the price that maximizes traffic flow. As Chris said, “Congestion pricing is hard.”  Although it seems complicated, you might be shocked at how easy it is, in concept, to price roads optimally.  That’s because it’s somewhat […]