Welcome to Caltrans District 4

101 Auxiliary Lane Project

This Project Has Been Completed

Route101 Auxiliary Lanes Project 3rd Avenue to Millbrae Ave San Mateo County | Complete Document 22MB

Project Description: The proposed project includes adding auxiliary lanes between 3rd and Millbrae Avenues in both northbound and southbound directions on US 101 in San Mateo County. From the north the auxiliary lanes will begin at the Millbrae Avenue Interchange and run through the Broadway, Peninsula and Poplar Avenue Interchanges ending at the 3rd Avenue Interchange. In addition to the auxiliary lanes, other major components of the project are as follows:

  • Reconstruct the Peninsula Avenue Overcrossing to: provide sufficient clearance between the columns for the proposed auxiliary lanes;

  • Reconstruct the Monte Diablo Pedestrian/Bicycle Overcrossing to provide sufficient clearance between the columns for the auxiliary lanes;

  • Construct a new Broadway Pedestrian/Bicycle Overcrossing: south of the existing Broadway Interchange; and

  • Construct retaining walls, sound walls at specific locations and landscape: specific areas within project limits.

Project Funding: This is a State/local partnership project and funding for the project is shared.

Project Purpose & Need: Reduce traffic congestion resulting from merging and weaving conflicts, improve overall system performance in the vicinity of the Peninsula Avenue Over crossing and the Highway 101 corridor between the Cities of San Mateo and Burlingame through construction of Auxiliary lanes.

General Project Development and Construction Information

  • This project is primarily designed by the San Mateo County Transportation Authority (SMCTA) with oversight from Caltrans.
  • Caltrans will perform construction administration
Project Initiation Document (PID):
Responsible Party: SMCTA
  • Caltrans approves Project Study Report (PSR) - 5/22/00.
Project Approval/Environmental Document (PA/ED):
Responsible Party: SMCTA
  • FHWA approves a draft environmental document (DED) for public review - 7/03.
  • Open House to solicit public input held - 8/19/2003
  • FHWA certifies/approves the Environmental Assessment/Initial Study (EA/IS) - 2/04.
  • BCDC permit issued - 12/15/06.
  • Caltrans approves PA/ED - 3/16/06.
Right of Way:
Responsible Party: SMCTA
  • R/W Certification issued - 4/11/06.
Responsible Party: SMCTA
  • Cooperative Agreement between SMCTA and Caltrans executed - 5/03/06.
  • Caltrans approves Project Plans & Specifications to RTL - 8/16/06.
RTL & Construction:
Responsible Party: Caltrans
  • California Transportation Commission (CTC) votes - 6/8/06 to allocate State funds
  • Ready to List (RTL) - 8/16/06
  • Project Advertised - 9/25/06
  • Bid Opening - 11/28/06
  • Contract Award - 2/23/07
  • Construction begins - 4/9/2007. Estimated construction period is approximately up to spring 2011.
  • Landscaping within the project limits – a 2-year plant establishment project will follow the roadway project.
To view the plans for this project you can contact Millbrae DPW or The City of San Mateo:
Karen Riley 650-522-7334 e-mail kriley@cityofsanmateo.org
Khee Lim 650-259-2347 e-mail klim@ci.millbrae.ca.us

Project Manager:
Nandini Shridhar

For further information, please contact us via letter, phone or email:

Gidget Navarro
Public Information Officer
Caltrans, Division of External Affairs
111 Grand Avenue - Mail Station: 6E
Oakland, CA 94612
Ph: (510) 510-286-5574
Email: gidget_navarro@dot.ca.gov