Bridging the gap: New East Bay overcrossing to connect major trail

For nearly two decades, the Highway 4 bypass has cut right through the Mokelumne Trail in Brentwood, blocking access and forcing pedestrians and cyclists to take a long detour on busy Lone Tree Way to continue on the path.

Finally, a bridge being built over the bypass will connect the two trail segments.

Years in the making, the bridge will close the gap created two decades ago when Highway 4 was expanded. By connecting the two sides of the Mokelumne Trail, the bridge will offer safe access for cyclists and pedestrians for commuting and recreational travel, according to officials.

“When that bridge is put in, you’ll be able to travel from the Bay Area all the way out to the Sierra Nevada,” Brentwood Mayor Joel Bryant said. “There’s a pretty extensive trail system that this connects to already.”

The Mokelumne Trail runs from the Martinez Regional Shoreline to the north, Oakland to the west, and Brentwood to the east passing through Antioch. It is part of the larger five-segment Mokelumne Coast to Crest Trail system, which when completed, will stretch from the East Bay to the Sierra Nevada.

Funding for the $13 million overcrossing will come from Measure J, the State Route 4 Bypass Authority and bridge toll funds.

Construction for the Contra Costa Transportation Authority Highway 4 bypass overcrossing began in March and is expected to be completed by spring. The project will have one of the shortest construction timelines in the authority’s history, officials said.

The 850-foot bridge features a 16-foot-wide trail to accommodate both bicyclists and pedestrians and meets Americans with Disabilities Act standards to support use by all community members. It will also be wide enough for future autonomous shuttles — small electric pod cars now in the development stage — that possibly could traverse the bridge in the future.

Bryant noted that Brentwood is one of the four East Contra Costa County cities planning to partner with Glydways, a South San Francisco firm, to test an on-demand autonomous electric pod car transit system.

“We’ll be working together with Glydways to have that system in place eventually, hopefully,” he said. “So this bridge will enable personal, autonomous vehicle technology to potentially use it as well. So people can have alternatives to the traffic on Highway 4.”

Antioch Mayor Lamar Thorpe, a member of East County Transportation Planning and a CCTA commissioner, also applauded the new bridge that will help Antioch connect via a trail to Brentwood and possibly accommodate other future transportation modes.

“The design is wide enough so that if we ever do use autonomous vehicles, they can easily maneuver through there,” he said in an interview. “But the primary purpose of that pedestrian bridge is obviously to connect the Mokelumne Trail and give pedestrian connectivity between Brentwood and Antioch.”

“You know, mobile transportation is important and a priority, but the higher importance here is getting people off of cars and into bicycles and alternative modes of transportation and better utilizing our trails that connect us that connect all of Eastern Contra Costa County.”

Thorpe noted that East Contra Costa County has high rates of obesity and diabetes and it’s important to promote healthy living and exercise.

“Over here in Antioch, we’ll have a ‘bicycle garden’ that will be part of that as well,” Thorpe said of the planned bicycle park with real-life traffic features to teach cyclists. “We’ll work toward really getting people, especially kids under 18, to really utilize their bicycles and make our city and that whole network (of trails) safer for pedestrians.”

The bridge will have other benefits as well, officials note.

The overcrossing is located in a 240-acre parcel south of Lone Tree Way and north of Sand Creek Road designated as a mixed-use, pedestrian transit zone. The bridge will connect pedestrians to the future Innovation Center at Brentwood, a workplace community that is planned as a high-tech business area and will include employers and housing.

An interim transit station, including a park-and-ride facility with bus service from Brentwood to Antioch, is also being evaluated for the site near the bridge. BART has also eyed the land there for a future eBart station, according to officials.

“It’s the first domino,” Bryant said of the overcrossing under construction.

“This is very important, both for the quality of life for our residents that enjoy the trails, as as well as providing an opportunity for people to maybe do a reverse commute to the jobs that are going to be in the Innovation Center and safely use that bridge to come to housing here, come to shopping here and still help address the concerns with traffic and greenhouse gases.”

Bryant also noted that the pedestrian/autonomous bridge and transit village that will be built nearby are important components to the East Contra Costa County partnership between cities.

“Each one of our communities has something to offer that the other one can take advantage of,” he said. “And so this bridge will help literally bridge the gap for the transportation access for our families in Brentwood, Antioch, Pittsburg Oakley. The autonomous vehicles will, and that would be really neat.”

More information about the overcrossing is available at https://ccta.net/projects/mokelumne-trail-bicycle-pedestrian-overcrossing/