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On-Ramp Metering on U.S. 101 in Sonoma County

In September 2014 the California Department of Transportation (Caltrans) activated ramp metering at 25 locations on southbound U.S. Route 101 in Sonoma County, from Arata Lane in Windsor to Pepper Road in Petaluma. In October 2014 Caltrans activated 18 ramp meters on northbound U.S. Route 101 from Gravenstein Highway in Cotati to Shiloh Road in Windsor.

In April 2015 Caltrans will activate the three remaining ramp meters at Airport Boulevard. The ramps were not activated in 2014 due to construction at Airport Boulevard.
  • Beginning Monday, April 13, 2015, ramp meters on northbound and southbound U.S. Route 101 at Airport Boulevard will be set to solid green during commute times to alert drivers to the new driving condition.
  • On Tuesday, April 21, ramp meters will cycle through red and green in the morning from 6 a.m. to 10 a.m. and in the afternoon from 3 p.m. to 7 p.m.
  • Caltrans will monitor the timing of the ramp meters and make adjustments as necessary.
What is Ramp Metering?

Ramp metering is a traffic management strategy using traffic signals and accompanying equipment and techniques to manage on-ramp flow on the freeway system. It is intended to improve the safety of vehicle merging and the flow of traffic on the highway. Motorists at newly activated ramp locations may experience operational delays during the first few days of operation. Caltrans staff will monitor the metered locations and make adjustments, and then fine tune the metering operations. Drivers entering U.S. Route 101 where ramp meters are activated should stop at red and wait until the traffic signal turns green to enter U.S. Route 101. Caltrans will monitor traffic conditions and operate ramp meters as appropriate.

Additional Information

Many of the on-ramps in Sonoma County have a carpool lane marked with a diamond. The carpool lane restriction for an on-ramp is 24-hours per day, seven days a week.

The Ramp Metering Information Line is: 510-286-4531. Or follow us on Twitter at: https://mobile.twitter.com/CaltransD4