Starting Saturday, you’ll be able to walk or bike across the Richmond-San Rafael Bridge 24 hours a day, seven days a week.

The 6-mile bike and pedestrian trail connecting Contra Costa and Marin counties will open at 10 a.m.

The community is invited to a ribbon-cutting celebration for the trail at 10 a.m. at 961 Stenmark Drive, just off the bike/pedestrian trail at Point Molate.

The local cycling advocacy group, Rich City Rides, is inviting the public to a group ride that will meet at Unity Park on the Richmond Greenway at 9 a.m. (ride begins at 9:30 a.m.). The group plans to ride across the bridge when it officially opens.

The $20 million trail project is part of the 500-mile San Francisco Bay Trail. It features a moveable barrier on the upper deck of the bridge that separates cyclists and pedestrians from auto traffic.

The project also includes new access from Point Richmond. A new 10-food wide, two-way, multi-use Bay Trail section has been constructed between Castro and Marine streets on the southern side of Interstate 580, crossing under I-580 at Marine St., continuing to Stenmark Drive on the north side of the freeway, and crossing the bridge to East Francisco Boulevard in San Rafael, according to Bruce Beyaert, chair of the Trails for Richmond Action Committee (TRAC).

“The 4.4-mile route across the bridge itself provides a pedestrian and bicyclist connection between the East Bay and North Bay and marks the sixth Bay Area bridge with the Bay Trail completed,” Beyaert said, adding that only the Bay Bridge west span and San Mateo Bridge now lack a Bay Trail crossing.

As part of the project, Chevron provided access to its land for construction of parts of the trail between Stenmark Drive and the bridge. In addition, Chevron has granted an easement along more than a mile of shoreline for the future construction of 2.5 miles of additional Bay Trail spanning from I-580 to the Pt. Molate Beach Park.