California Department of Transportation

US Highway 101/Santa Maria River Bridges Widening

Project Information

Project Proposal: 
The Santa Maria River Bridge Widening Project will expand a four-lane bridge to six lanes, create safer access from SR 135 to SR 166 (north of the river) and extend a six-lane section across the river to the SR 166 East corridor.  It will add capacity to accommodate forecasted traffic demand and improve traffic safety.  It will also add a Class I bicycle path across the bridge.  US 101 is a major north-south corridor between the San Francisco and Los Angeles area.  At this gateway location, it is the major north-south corridor between Santa Barbara and San Luis Obispo Counties, and a designated focus route, a high emphasis route, as well as being designated a Focus track project.  Average daily traffic counts are 64,000, growing to 100,700 by 2030.  Trucks make up about 7.4 percent of the total traffic in the project area.  The project has a strong three-way partnership and support between SLOCOG, SBCAG and Caltrans.   All three agencies have contributed funding to the project.  To view the project overview PowerPoint, click here.

Status of Project
Flat Iron West Inc. was the lowest bidder for this project, with a contract bid of $30.9 M.  Construction will begin early fall 2011 and conclude in 2015. The Prop 1B CMIA program will contribute $24.5M to construction with matching funding committed in the amount of $2.5 M from SLOCOG and $7.8 M from SBCAG.

Co-Sponsors:  SLOCOG, SBCAG, Caltrans

**Bicyclists should be aware of limited shoulder space on the bridge at all times during construction.  The following detour for bicyclists is recommended.  Bicyclists traveling southbound can detour along Thompson Avenue to State Route 166 East to Bull Canyon Road to Donovan Road.  Bicyclists traveling northbound can detour along Donovan Road to Bull Canyon Road to State Route 166 West to Thompson Avenue.


For general questions please contact:

Caltrans District 5, Public Affairs Department
Department of Transportation
50 Higuera Street
San Luis Obispo, CA 93401

(805) 549-3318





Last updated: August 21, 2012