Skip to Content
Streetsblog USA home
Streetsblog USA home
Log In

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

Traffic engineers can generally predict the high-demand days, but there's a fair amount of randomness in traffic patterns. Some days an unusually large number of drivers just happen to drive to work at the same time.

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

Price changes might affect the behavior of drivers who are about to enter the highway.  But they are just a fraction of the drivers targeted by congestion pricing. Congestion prices are also intended to shift drivers' time of travel and mode of transportation. That requires getting them the price in advance, in real time (via the Internet, for example). But that, in turn, creates a real risk of herd behavior. If the posted price is high, most drivers will respond by taking alternate routes or leaving too late. If the posted price is low, drivers will rush to their cars to take advantage of the low tolls, creating a sudden surge in demand and unnecessary spikes in prices.  There's a sort 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.

Stay in touch

Sign up for our free newsletter

More from Streetsblog USA

‘We’re Not Copenhagen’ Is No Excuse Not to Build a Great Biking And Walking City

A team of researchers identified eight under-the-radar cities leading the local active transportation revolution — and a menu of strategies that other communities can and should steal.

June 30, 2025

Monday’s Headlines, Ranked

New reports rank the best cities for biking and the best complete streets policies. Plus, the robotaxi wars have begun.

June 30, 2025

Washington State Is About To Have the First Pro-‘Woonerf’ Law in America

Washington state is making it legal for cities to have people-centered streets in a first-in-the-nation law.

June 30, 2025

Friday’s Headlines Are Doomed

Philadelphia transit is falling off the fiscal cliff, with other major cities not far behind. And the effects of service cuts on their economies could be brutal.

June 27, 2025

Talking Headways Podcast: Why We Need ‘Universal Basic Mobility’

In a very special podcast, we’re joined by the great Madeline Brozen of UCLA to talk about how guaranteed transit lowers people's stress.

June 26, 2025
See all posts