Carpool cheats on favorite back door to Bay Bridge forces changes

Commuters head eastbound on the Bay Bridge. Commuters head eastbound on the Bay Bridge. Photo: Eric Luse Photo: Eric Luse Image 1 of / 28 Caption Close Carpool cheats on favorite back door to Bay Bridge forces changes 1 / 28 Back to Gallery

Every driver loves a quick way to sneak onto the Bay Bridge. But some commuters are about to lose a favorite backdoor route: the oft-congested Sterling Street-Bryant Street on-ramp.

Hoping to unclog the eastbound on-ramp, transportation officials want to restrict access to carpoolers only earlier in the day — starting at midday. They also plan a crackdown on cheaters — who make up as much as 50 percent of the ramp’s traffic — and may use high-tech cameras and devices to help the California Highway Patrol with enforcement.

The plan, which needs approval from Caltrans and the Metropolitan Transportation Commission, is part of a multifaceted effort to decongest Bay Area carpool lanes. More than half of the region’s carpool lanes fail to meet federal standards for speed, and several have grown sluggish over the past few years.

“The Sterling-Bryant ramp is one place we think we can make a big difference with some quick hits,” said Andrew Fremier, deputy executive director for operations at the MTC.

Situated near the top of Bryant Street, the on-ramp puts drivers right onto the bridge. For years, its location on the south side of the bridge, nestled along narrow streets, was an effective shortcut. But it’s become increasingly popular and, on weekdays, backs up well before 3:30 p.m., when it becomes a lane restricted to cars with three or more occupants or clean-air vehicles.

Fremier said the ramp often backs up by 2:30 p.m., giving carpoolers little advantage during restricted hours.

“Once it’s degraded, it never recovers,” he said.

No decisions have been made on how early the lane should become closed to non-carpoolers, he said. When the ramp is open only to those who qualify for the carpool lanes, it becomes crowded with scofflaws, many of them solo drivers.

CHP officers occasionally blitz the on-ramp, but the MTC is looking into whether new types of cameras, some of which have been tested in Southern California, could be used to help determine the number of occupants in a car. Under state law, those cameras couldn’t automatically issue citations and mail them, but they could alert CHP officers in the area who could then write citations, Fremier said.

The drive to make carpool lanes more efficient is also focusing on Highway 101 in Marin and Sonoma counties, where congestion has worsened noticeably, slowing carpoolers and Golden Gate Transit buses. The MTC wants to lengthen the hours carpool lanes operate — currently from 6:30 to 8:30 a.m. and 4:30 to 7 p.m. — with morning hours extended to 10 a.m. and evening hours starting at 3 p.m.

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com Twitter: @ctuan