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The View of Congestion Pricing from Texas

9:13 AM PDT on April 17, 2009

Remember congestion pricing? It's not much fun to think about what happened to that idea in New York last year. And considering the craziness
that's been going on over bridge tolls in Albany, any kind of road
pricing in our fair city certainly seems like a non-starter for the
foreseeable future.

3185072987_0406df62ca_1.jpgTraffic in Austin. Photo by .nutter via Flickr.

But in Texas, Streetsblog Network member Austin Contrarian
is living up to his name with a post that holds out hope that
congestion pricing's time is indeed coming, and considers some
practical issues of implementation:

Here's the information problem:  The optimalcongestion toll should be set just high enough to achieve free-flow (45mph) traffic. But if the toll is set too high, it will induce too manydrivers to shift to other times, routes or modes of transportation.That's bad, too (atleast if you ignore other externalities like pollution.)

Trafficengineers can generally predict the high-demand days, but there's afair amount of randomness in traffic patterns. Some days an unusuallylarge number of drivers just happen to drive to work at the same time.

Theoptimal toll therefore should be variable -- the greater the demand,the higher the toll.  But that's very hard to implement as a practicalmatter. How do we get would-be drivers the information they need tomake timely decisions? There's no point in raising prices on driversonce they've entered the road; raising prices can no longer influencetheir behavior (except perhaps to launch them into a homicidalrampage). 

Pricechanges might affect the behavior of drivers who are about to enter thehighway.  But they are just a fraction of the drivers targeted bycongestion pricing. Congestion prices are also intended to shiftdrivers' time of travel and mode of transportation. That requiresgetting them the price in advance, in real time (via the Internet, forexample). But that, in turn, creates a real risk of herd behavior. Ifthe posted price is high, most drivers will respond by taking alternateroutes or leaving too late. If the posted price is low, drivers willrush to their cars to take advantage of the low tolls, creating asudden surge in demand and unnecessary spikes in prices.  There's asort of Heisenberg uncertainty principle at play.

Other good things from around the network: The Transport Politic digs deeper on Obama's high-speed rail anouncement. Orange County Transit Blog reports bus riders there aren't taking cuts lying down. And EcoVelo links
to a truly cool opportunity: you can help fund a bike-repair school in
Mauritania that's being set up by a Peace Corps volunteer.

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