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Mokelumne Trail Overcrossing Now Open – Richmond-San Rafael Bridge Path at Risk

Author: Bike East Bay

Date: March 22, 2024

Aerial photo of the Mokelumne Trail Overcrossing of Hwy 4 between Brentwood and Antioch

This article is part of our Bridging the Bay campaign, providing info updates and organizing opportunities for proposed and existing bike bridges across the East Bay.

Visit the campaign page by clicking the button below, and sign up for our notification list to get involved.

This past week our Bridging the Bay campaign celebrated a major win, and received an unwelcome surprise that we need your help with. But first the good news… 

The Mokelumne Trail Overcrossing is Open!

photo of a group of people posing with a ribbon and giant scissors in front of the new Mokelumne Trail Overcrossing

Many decades in the making, the Mokelumne Coast-to-Crest Trail overcrossing of Hwy 4 between Brentwood and Antioch opened with a grand celebration on March 20, 2024.

Spanning just 850 feet, this bridge connects two halves of a trail further bisected by a freeway expansion in 2014.

A gap closure facility was promised as part of the project’s environmental analysis, but for the following ten years the only nearby option remained the harrowing Lone Tree Way interchange, shared with high speed car traffic.

map of the Mokelumne Trail showing the crossing location at Hwy 4

Thankfully longtime advocate and Bike East Bay member Ole Ohlson (photos below) didn’t allow decision makers to forget about their obligation, and along with former Brentwood Mayor Bob Taylor they kept this project alive and finally prioritized for construction.

At a total cost of $13M, this bridge was paid for via funds from Contra Costa’s Measure J as well as Regional Measure 3 bridge toll funds, each of which Bike East Bay campaigned to help win.

But it is so far the only dedicated bike/walk overcrossing along the entire 35 miles of Highway 4 from Hercules to Brentwood. Many more like it are still needed.

The grand opening event was attended by staff members from the Contra Costa Transportation Authority, elected officials from Brentwood, Antioch, and Contra Costa County.

Members of the public included active transportation groups such as the Delta Pedalers bike club, the GirlTREK Black womens’ walking team, and our own Bike East Bay contingent doing a loop ride from the Antioch eBART station.

We heard some great quotes from elected officials during the grand opening remarks, including:

“When we built this freeway (Hwy 4) it became its own barrier, and this is about breaking it down.”  -Contra Costa Transportation Authority Chair and Danville Councilmember Newell Arnerich

“It’s like a quilt when we’re building these trails, sometimes it’s big pieces and sometimes little pieces. Today is a big piece.” -Contra Costa County D3 Supervisor Diane Burgis

“Bridges are about connections. One of the benefits is being able to connect with your neighbors and people you haven’t met before.” -Brentwood Mayor Joel Bryant

We couldn’t agree more, and the same could be said about every one of our critical bike/walk bridge path connections. Which brings us to our second update…


The Metropolitan Transportation Commission Wants to Close the Richmond-San Rafael Bridge Path

We are intensely disappointed and surprised about a recent Metropolitan Transportation Commission (MTC) staff proposal to eliminate weekday bike/walk access on the Richmond San Rafael Bridge, without any of the public process & study that was promised at the start of the 4-year pathway pilot project approval.

More information about this pilot project process is available in our previous blog post here, referencing data collected so far that was supposed to inform any decision making.

The data shows that the bridge path did not adversely affect car congestion or pollution, and even resulted in some safety benefits for drivers. A study of the 4-year pilot project will be released later this summer with public engagement to follow.

Bay Area Toll Authority presentation slide "No Increase in Westbound Congestion • Duration of AM (Tues-Thurs) congestion is 30 mins shorter in Sept/Oct 2022. • Max. Queue Length is 0.2 mi. longer in Sept/Oct 2022."
Bay Area Toll Authority presentation slide from November 2023 on the bridge pathway pilot impacts

The primary opponents to the pathway have been the industry group Bay Area Council, who via their front org Common Sense Transportation Coalition have spent what we believe to be $100k or more on blatantly misleading propaganda mailers and ads.

Below is a screenshot from their website which continues to claim that “the traffic backup on the bridge is the number one source of non-wildfire air pollution in Richmond.”

The author of the study they cited for this claim has refuted their conclusion, as the largest source of pollution in Richmond is by a huge margin the Chevron refinery.

Coincidentally, Chevon is represented on the board of the Bay Area Council.

"What are the benefits of opening the third lane? GET THE RICHMOND BRIDGE MOVING Petition By opening the third lane, we can save commuters time and help alleviate the air pollution in Richmond. Currently, the traffic backup on the bridge is the number one source of non-wildfire air pollution in Richmond. This pollution causes adverse health effects in already suffering front line communities and we can help stop it."

What exactly is the MTC proposing?

The proposal right now is to close the bike/walk pathway all day on Mondays through Thursdays, and only opening it to people biking or walking on Fridays through Sundays.

This would be done by shifting the existing movable zipper barrier back and forth to create a 10-foot wide break down shoulder where the pathway is currently.

This would not result in a third car travel lane, though we are concerned that some drivers may try speeding in the break down lane, creating safety issues.

Why isn’t a third car lane proposed?

A third westbound car lane on the upper deck of the bridge is proposed, but such a change requires significant environmental analysis and mitigation.

A years-long process has been initiated to understand if this can be achieved on the current bridge, what the impacts would be, and to weigh this option against other alternatives.

Other changes to the bridge to alleviate congestion such as an update to the Richmond Parkway interchange and an “open road tolling” project to remove the toll plaza and most of the lane merges (the main westbound pinch point) are underway, but will also take a number of years for design and implementation.

In comparison, the current breakdown shoulder proposal is being rushed through without adequate analysis to know whether it will be helpful at all, at the expense of people biking and walking.

when would this change occur?

MTC staff have indicated that they want to make this change as soon as possible, but they need to get several approvals from appointed boards first.

This process will likely happen during meetings scheduled in May and June, with any approved changes being implemented after that.

One of these boards is called the Bay Conservation and Development Commission (BCDC), which was formed starting in the 1960s with two purposes: 1) To resist further landfill development into the San Francisco Bay, and 2) To increase public access to the SF Bay Shoreline and Bay Trail.

The Richmond-San Rafael Bridge bike/walk path is a major part of the Bay Trail, and it is clear that closures of the pathway will impact public access negatively, and that the BCDC should oppose this in alignment with their charter.

What can I do to help?

Email or call your representatives on the Bay Conservation and Development Commission!

All of the 27 BCDC commissioners are appointed, and many of them are elected officials representing constituents around the Bay Area.

Below is a list of BCDC commissioners elected to Bay Area offices, and their contact info. We encourage you to contact them by email or phone to let them know you oppose MTC’s proposal to close the Richmond-San Rafael Bridge pathway Monday through Thursday, and that it should be open 24/7 for transportation and recreation purposes just like other Bay Area bridge pathways.

You should request that they vote to deny MTC’s request for an amendment to their permit for the bridge path, at the May BCDC meeting.

Please keep your remarks respectful, and talk about your own experiences with the bridge path, what it enabled you to do and how it made you feel. Also let them know the city where you live, and if you are a constituent of theirs.

BCDC Member Contact Info

Contra Costa County


  • Lena Tam, Alameda County District 3 Supervisor

Marin County

  • Stephanie Moulton-Peters, Marin County Board of Supervisors


  • Susan Gorin, Sonoma County Board of Supervisors

NAPA County

  • Belia Ramos, Napa County Board of Supervisors


  • Mitch Mashburn, Solano County Board of Supervisors

San Francisco COUNTY/CITY

  • Aaron Peskin, San Francisco District 3 Supervisor


  • Dina El-Tawansy, Caltrans District 4 Director
  • Jenn Eckerle, California Natural Resources Agency

BCDC CHair & vice Chair


Tell Us Your Bridge Path Story

If you are a weekday bridge path user, we want to hear from you. Fill out the form below and we will follow up if we have questions and would like to get your permission to share your responses.

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This article is part of our Bridging the Bay campaign, providing info updates and organizing opportunities for proposed and existing bike bridges across the East Bay. Click the button below to sign up for our notification list to get involved.

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