SB 101 Metering Lights Turned On Full Cycle May 5th

South San Francisco, CA    May 5, 2015            Submitted by Caltranscaltrans logo

U.S.101 San Mateo County Ramp-Metering Project

Where are the metering lights located?

Caltrans and its project partners are installing ramp meters on U.S.101 at various onramp locations between State Route 92 in San Mateo and the San Mateo/San Francisco County line.

What are the specific ramp locations?

Ramp meters have been installed at 17 onramps in the southbound direction of the U.S. Route 101 Ramp Metering Project. They include the following locations along northbound Route 101:

  1. Southbound Route 101 and Beatty Avenue
  2. Southbound Route 101 and Lagoon Road
  3. Southbound Route 101 and Airport/Bayshore Road
  4. Southbound Route 101 and Oyster Point Boulevard
  5. Southbound Route 101 and ProduceAvenue/Airport
  6. Southbound Route 101 and I-380 Westbound/N.Access Road
  7. Southbound Route 101 and San Bruno Diagonal
  8. Southbound Route 101 and SFO International Terminal
  9. Southbound Route 101 and SFO Domestic Terminal
  10. Southbound Route 101 and Millbrae Avenue Westbound
  11. Southbound Route 101 and Millbrae Avenue Eastbound
  12. Southbound Route 101 and Broadway/Rollins Road
  13. Southbound Route 101 and Poplar Avenue
  14. Southbound Route 101 and 3rd Avenue Westbound Loop
  15. Southbound Route 101 and 4th Avenue Eastbound Diagonal
  16. Southbound Route 101 and Fashion Island Drive
  17. Southbound Route 101 and SR 92 Eastbound Diagonal


What happens when they are activated? What should I do?

Ramp metering will begin in the southbound direction of U.S. Route 101 in San Mateo County at 17 locations from the San Francisco/San Mateo County line and State Route 92 in San Mateo.


April 28, 2015, ramp meters will be activated, but meters will rest in green. May 5, 2015, ramp meters will start cycling during southbound PM peak time from 2:30pm to 8:00pm. May 12, 2015, ramp meters will start cycling during southbound AM peak time from 6:00am to 10:00am.


All on-ramps will operate at “1 car per green” except for one freeway to freeway connector ramp which will meter and operate at “2 cars per green”. The one freeway connector is the eastbound State Route 92 to southbound U.S. 101 Connector.


What else should I know about ramp meter operations?

The ramp meters may start off resting-in-green and start metering when conditions on the freeway mainline needs metering. The meters may also remain green the whole peak period due to issues with available storage on the on-ramp. Once the ramp starts metering the signal lights will cycle red-green. Caltrans will monitor conditions. Be aware as you approach ramp meters as you may need to stop and follow the indicators on the ramp metering signal head. Also, you should watch for “METER ON” advance warning signs. These signs warn motorists that the on-ramp is metered, and of approaching slowdowns at metered on-ramps. You do not need to stop at a dark signal at a metered on-ramp.

Following activation, Caltrans will monitor ramp metering vehicle activity and optimize systems as needed. In addition, ramp meters could be subject to time changes based on monitoring results.

Who made the decision to activate ramp meters in San Mateo County?

Caltrans, City County Association of Governments of San Mateo County (C/CAG), Metropolitan Transportation Commission (MTC)


What is ramp metering? How will it benefit me?

Ramp metering is a traffic management strategy, which uses traffic signals and accompanying ramp metering equipment and techniques to improve flow on the freeway system by managing the on-ramps.


Where can I go online to get the latest project information and traffic information?

For additional project information, including maps, pictures and other project-related information, visit us at:


For the latest traffic information, follow us on Twitter at:


Is there someone I can contact if I have additional questions?

You can email or call the following people:

California Department of Transportation (Caltrans)

Gidget Navarro, Caltrans Public Information Officer, San Mateo County


Metropolitan Transportation Commission (MTC) John Goodwin, Public Information Officer 510-817-5862

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8 years ago
Reply to  Editor

They put the Light at the END of the Ramp entering 101 South. So when the light turns GREEN you have 10 yards to accelerate to 65MPH as you enter traffic. This is insane.