Mokelumne Trail Bicycle and Pedestrian Overcrossing

Highway 4 Mokelume Trail logo



The Mokelumne Trail Bicycle and Pedestrian Overcrossing project will construct a bridge spanning Highway 4 in Brentwood, closing a gap in the trail that was created by the highway’s expansion. In connecting two sides of the Mokelumne Trail, the bridge will provide safe access to cyclists and pedestrians for commuting and recreational travel.

Design Highlights

  • Multi-span bridge with a column in the Highway 4 median
  • Bridge approaches will be constructed on earthen embankments
  • Path will range from 12 to 16 feet in width
  • Width will accommodate the potential for future autonomous shuttle travel


ANTICIPATED COMPLETION: Late Summer or Early Fall of 2023

Costs & Funding

The cost to design and build the bridge is approximately $13 million, with funding provided through Measure J taxpayer dollars, the State Route 4 Bypass Authority, and bridge toll funds.

Mokelumne trail bus icon

The overcrossing will provide access and connection to the future East County Intermodal Transit Center in Brentwood.

mokelumne trail icon

The Mokelumne Trail in the overcrossing project area is part of the larger Mokelumne Coast to Crest Trail that will, when completed, connect six counties across California from the East Bay to the Sierra Nevada Mountains.

Mokelumne Map

For more info about this project, contact:

Ivan Ramirez, Director, Construction
Contra Costa Transportation Authority

Traffic Advisory

State Route 4 Westbound Overnight Closures Planned in Brentwood this Friday, August 18 & Saturday, August 19

In partnership with the City of Brentwood, the Contra Costa Transportation Authority (CCTA) is constructing the Mokelumne Trail Bicycle and Pedestrian Overcrossing to provide safe access to cyclists and pedestrians for commuting and recreational travel, reconnecting two sides of the trail that were separated by the expansion of State Route 4. These overnight closures will facilitate the removing of the temporary structure that was used to support the bridge, and will impact State Route 4 in the westbound direction. CCTA and the California Department of Transportation (Caltrans) have scheduled the closures during the late evening and early morning hours in order to minimize impacts to the motoring public.

Overnight Westbound Freeway Closure of State Route 4 between Lone Tree Way and Sand Creek Road

In order to ensure crew and public safety during the planned construction work, temporary nighttime freeway closures in the westbound direction of State Route 4 will occur between Friday, August 18 and Sunday, August 20, 2023 on the following schedule (weather permitting):

  • Westbound SR-4 will be closed from Friday, August 18, at 9:00 p.m., until Saturday, August 19, at 6:00 a.m. It will be closed again from Saturday, August 19, at 9:00 p.m., until Sunday, August 20, at 7:00 a.m.
  • Eastbound SR-4 lanes will remain open during the westbound closures.


Detours will be in place to reroute drivers around the closure and are planned as follows:

  • Westbound drivers having to detour will exit on Sand Creek Road and go eastbound on Sand Creek Road to Shady Willow Lane, then northbound on Shady Willow Lane to Lone Tree Way, and proceed westbound on Lone Tree Way to the westbound State Route 4 on-ramp.

Future Freeway Closures

Additional overnight closures may be needed over the course of the next several weeks (weather dependent) to facilitate construction work of the future Mokelumne Trail Bicycle and Pedestrian Overcrossing. Additional information regarding dates and detours will be provided once the schedule is confirmed. This project is anticipated to be complete in late summer or early fall of 2023.