Ramp Metering Project | Operate + Coordinate | Our Work

Ramp Metering Project

Ramp meters, or traffic signals on freeway on-ramps, work.

Ramp meters not only reduce freeway congestion, but they cost just a fraction of a typical widening project — and can be installed comparatively quickly.

Metered on-ramp

Credit: Noah Berger

Our Freeway Performance Initiative aims to install metering lights on some 300 freeway on-ramps around the Bay Area.

Similar to traffic signals on a busy street, ramp meters manage the flow of traffic entering a freeway, which:

  • Makes merging easier
  • Reduces potential for accidents
  • Reduces freeway congestion by smoothing out traffic flows
  • Delivers more consistent and reliable travel times
  • Improves air quality

MTC works closely with the California Department of Transportation (Caltrans), county congestion management agencies and city governments to fine-tune ramp-metering projects to the unique demands of various freeway corridors.

ramp meter in \"on" mode
John Huseby, Caltrans
Beleaguered motorists stuck on Interstate 80 between the Carquinez Bridge and the Bay Bridge, one of the busiest commutes in the Bay Area, are all too familiar with gridlock and slow-and-go traffic. But smart solutions are on the way via the I-80 SMART Corridor Project (SMART is an acronym for Safety, Mobility, Automated Real-time Traffic Management). The project will feature one of the most extensive Intelligent Transportation Systems in California, integrating communication technologies into the transportation infrastructure to improve safety and mobility. Adaptive ramp meters — which adjust green time based on prevailing conditions —  will manage the flow of traffic onto and along I-80 in real time based on prevailing conditions, making it safer for drivers to merge onto the interstate. Some ramps give priority to high-occupancy vehicles (HOVs) and transit. Read more.

Freeway travel times dropped sharply after the installation of ramp meters in many parts of the Bay Area:

  • Alameda County /I-580/ Foothill Road to North Flynn Road
    Down 37 percent
  • San Mateo County /U.S. 101/ San Mateo to Palo Alto
    Down 30 percent
  • Solano County /I-80/ Red Top Road to North Texas St.
    Down 25 percent
  • Sonoma County /U.S. 101/ Petaluma to Windsor
    Down 9 percent