Computing Community Consortium Blog

The goal of the Computing Community Consortium (CCC) is to catalyze the computing research community to debate longer range, more audacious research challenges; to build consensus around research visions; to evolve the most promising visions toward clearly defined initiatives; and to work with the funding organizations to move challenges and visions toward funding initiatives. The purpose of this blog is to provide a more immediate, online mechanism for dissemination of visioning concepts and community discussion/debate about them.

“Incentives for Drivers Who Avoid Traffic Jams”

June 12th, 2012 / in Research News / by Erwin Gianchandani

If you’re like most of us, you’ve already spent some time stuck in traffic today. As it turns out, on average, each of us spends 50 hours in congestion every year. Well, Stanford University computer scientist Balaji Prabhakar is experimenting with a possible solution — incentive-based approaches, from reward points to lottery cash prizes, that encourage a portion of rush-hour commuters to shift their commutes to the hour before or after peak travel times. The New York Times‘s John Markoff has an excellent piece describing Prabhakar’s work — including early trials on the Stanford campus, in Bangalore, and in Singapore — in today’s Science Times:

Chinmoy Mandayam, a graduate student at Stanford, adjusted a solar-powered traffic scanner [image courtesy Tom Yue/The New York Times].London, Singapore, Stockholm and a few other cities around the world battle heavy traffic with a “congestion charge,” a stiff fee for driving in crowded areas at peak hours. But drivers generally hate the idea, and efforts to impose it in this country have failed.


Balaji Prabhakar, a professor of computer science at Stanford University, thinks he has a better way.


A few years ago, trapped in an unending traffic jam in Bangalore, India, he reflected that there was more than one way to get drivers to change their behavior. Congestion charges are sticks; why not try a carrot [more following the jump…]?


So this spring, with a $3 million research grant from the federal Department of Transportation, Stanford deployed a new system designed by Dr. Prabhakar’s group. Called Capri, for Congestion and Parking Relief Incentives, it allows people driving to the notoriously traffic-clogged campus to enter a daily lottery, with a chance to win up to an extra $50 in their paycheck, just by shifting their commute to off-peak times.


The program has proved so popular that it is to be expanded soon to also cover parking.


Amaya Odiaga, the director of business operations for Stanford’s physical education department, now drives to campus a few minutes earlier and says she has won just $15. But a co-worker got $50 — creating a competitive atmosphere that makes the program fun, Ms. Odiaga said.


Better yet, Ms. Odiaga’s commute now takes as little as 7 minutes, down from 25 minutes at peak hours.


Dr. Prabhakar is a specialist in designing computer networks and has conducted a variety of experiments in using incentives to get people to change their behavior in driving, taking public transit, parking and even adopting a more active lifestyle. Unlike congestion pricing, which is mandatory for everyone and usually requires legislation, “incentives can be started incrementally and are voluntary,” he said.


Moreover, systems based on incentives can offer a huge advantage in simplicity. Until recently, the Stanford system required sensors around campus to detect signals from radio-frequency identification tags that participants carried in their cars. But the need for such an infrastructure has vanished now that so many drivers carry smartphones with GPS chips or other locaters.


Administrators can use the network to set up a centralized Web-based service to manage any number of incentive campaigns.


“Through smartphones we’re getting more at ease about fine-grained information about space and time,” said Frank Kelly, a mathematician at the University of Cambridge in England who specializes in traffic networks. “This is possible because information and communications systems are becoming cheaper and cheaper.”



Dr. Prabhakar’s experiments have offered different kinds of incentives, from airline-style reward points to lottery cash prizes. Now his system is poised to reach a much larger audience.


Singapore is considering a system he and his students designed that offers lottery participation or a fare discount to public transit riders who travel at off-peak times. A trial run begun in January lowered rush-hour ridership by more than 10 percent. (Given a choice between discounts and lottery, riders overwhelmingly chose the lottery.)



The Stanford experiment adds a social network component to the lottery, in effect making it a game where friends can observe one another’s “good” behavior. The researchers say this tends to reinforce changes in behavior and individual commitment. Next fall, the university plans to expand the system to encourage people to park farther from the busiest parking structures.



Dr. Prabhakar said the power of his method was that only a small change could have a drastic effect.

“This is one of the nicer problems,” he said. “You don’t have to change everyone’s behavior; in fact, it’s better if you don’t.”

Check out the full story in today’s Science Times — and learn more about Prabhakar’s research through his website.

(Contributed by Erwin Gianchandani, CCC Director)

“Incentives for Drivers Who Avoid Traffic Jams”

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