The agency launched the pilot bus project in December because many customers said they wanted more service between the two regions.
To get people to ride the new service, which linked bus routes 40 and 42, the district spent $100,000 on a marketing campaign involving posters at BART stations and a billboard on Interstate 580.
Despite initial customer interest and the agency's attempts to get people to take the bus line, Route 580 never caught on.
"The stops don't work for many customers," Clemens said. "The bus at this point doesn't represent any time savings for most drivers."
Traffic on the Richmond-San Rafael Bridge gets jammed up during commute hours and the bus offered little help, she said. Riders also complained that Route 580 did not connect with any BART stations.
The pilot project, five westbound morning trips and five eastbound afternoon commute trips, was set for nine months and will most likely end on Sept. 12.
Much of the $550,000 used to operate the service and the money to market the project were Regional Measure 2 funds administered by the Metropolitan Transportation Commission.
"We do need to experiment sometimes," MTC spokesman John Goodwin said in an interview. "It was a short-lived pilot program and now it's back to the drawing board."
To that end, Golden Gate Transit officials are considering whether to add service along its Route 40 line between San Rafael and BART's El Cerrito Del Norte station, Clemens said.
Construction is set to begin later this year to add a third eastbound lane on I-580 on the Richmond-San Rafael Bridge, according to Goodwin.
MTC and Caltrans planners are also considering making the bridge's toll system all-electronic, like the Golden Gate Bridge.
"The transit puzzle between the East Bay and Marin is a little bit tricky," Goodwin said. "Over time we'll look at various combinations and see if we can find something in conjunction with Golden Gate that will serve a greater number of passengers more conveniently."