S. Main St. construction project

The Contra Costa Transportation Authority (CCTA) and project partners are making great strides toward successful construction of 11 miles of new express lane on southbound I-680 (SB I-680) from Marina Vista Avenue in Martinez to around Livorna Road in Alamo. In order to open new lane capacity to motorists ahead of schedule, CCTA and the contractor mutually agreed to an accelerated and ambitious project schedule that was designed to complete multiple stages of work concurrently. Construction is proceeding almost a year ahead of schedule, and the new lane capacity for 2+ carpools is anticipated to open in Fall 2020. When the new lane opens, there will be visible signage for an express lane, but the new lane will operate as a high-occupancy vehicle (HOV) 2+ carpool lane during systems testing through at least the end of this calendar year. Operation of the lane as a tolled express lane is expected to begin in early 2021.

To facilitate a key phase of construction, CCTA and the contractor have scheduled a two-week closure of the southbound South Main Street on-ramp loop to SB I-680. The closure is scheduled to begin on Sunday, July 5 at 10:00p.m., with the on-ramp reopening on Monday, July 20 at 12:00 a.m. Signs will be in place before and during the closure. The detour route from the closed southbound South Main Street on-ramp loop will be to continue to the Rudgear Road on-ramp for access onto SB I-680. Only traffic utilizing the SB I-680 on-ramp from South Main Street in Walnut Creek will be impacted.

The project entails SB I-680 widening work between North Main Street in Walnut Creek to just south of Rudgear Road in Walnut Creek, in order to create new lane capacity. In preparation for the opening of a new lane, key construction activities include:

  • Completion of retaining walls and construction of sound walls between the freeway ramps at South Main Street in Walnut Creek
  • Completion of the median concrete barrier between Rudgear Road and Livorna Road
  • Removal of construction K-rail and completion of express lane signing and striping
  • Electronic tolling system testing
  • Removal of temporary driver education signs

Motorists are advised to be on alert for on-site closure and detour signs and to “Slow for the Cone Zone.” Please drive with caution through the detours and leave a safe traveling distance between your vehicle and the vehicle ahead of you. Please note that the construction schedule and closure information presented here are subject to change based on weather and other conditions. The majority of work is to be completed during the day, however, there may be moderate noise impacts at night due to concrete trucks and backup alarms. We appreciate everyone’s patience and cooperation as we work to complete these important improvements.

Express Lanes provide travel choices for the motoring public, improving mobility and freeway operations. Once tolling begins, use of express lanes requires a FasTrak Flex Toll Tag. Carpools and other eligible vehicles travel toll free or pay half-price tolls. Solo drivers pay full tolls.

For more information, visit the project website at 680xpresslanesproject.com or call the Project Information Line at (925) 206-3019. Follow the project on Twitter at: @SB680xpresslane