Search title image

TRANSACTIONS NEWSLETTER ONLINE

Bookmark and Share

Fall 2010

Award of Merit:
Peninsula Ramp-Metering Project Speeds Commutes, Cuts Red Tape

San Mateo County’s ramp-metering program is a model of interagency cooperation. (Photo: Noah Berger)

Installing metering lights on freeway on-ramps is one thing. But turning them on can be something else altogether, with a lengthy local approval process. Thanks to a pioneering collaboration between Caltrans, the cities of San Mateo County and the City/County Association of Governments of San Mateo County (C/CAG), the Bay Area now has a model for how to speed both the wheels of government and the wheels on commuters’ cars.

Travel times during peak periods along southbound U.S. 101 from San Mateo to Palo Alto dropped nearly 30 percent in early 2007 — from about 35 minutes to just under 25 minutes — after metering lights were turned on at seven on-ramps along the roughly 12-mile stretch from State Route 92 to the Santa Clara County line. Yet the project’s most important legacy may be found not amid the asphalt and concrete of the Bay Area freeway network, but in the region’s city council chambers and county supervisors’ board rooms.

“The partnership with C/CAG is more of a process innovation than it is a technology innovation,” explained Alan Chow, office chief and supervising transportation engineer for Caltrans District 4.

The journey toward a faster commute started back in 2002 when C/CAG Executive Director Richard Napier approached Caltrans about developing a ramp-metering strategy for the whole county. “Our initial problem was getting San Mateo County’s cities to even allow a study of activating the lights,” recalled Napier.

To satisfy concerns about backups onto local streets, the partners agreed to install “spill-back” detectors on each on-ramp. When the detectors are tripped by a long line of waiting cars, the lights go all green until backups are eliminated. To address concerns about local control, a technical advisory committee — including city, C/CAG and Caltrans staff — was formed to manage operations of the metering lights. No party can unilaterally adjust the signal timing.

“The process we followed is transferable to the rest of the region,” Napier said. “It’s gratifying to see how well the metering lights have been accepted. We cut travel times by 10 minutes, and the price is typically just 20 to 25 seconds on the on-ramp. That’s a small price to pay for such a big payoff.”
— John Goodwin

Video Profile: Highway 101 Ramp Metering Project

Transactions Fall 2010 Issue: Contents