Plan for Bay Bridge bike path from Oakland to S.F. in high gear

Cyclists ride by the Bay Bridge eastern span’s tower on the Alexander Zuckermann bicycle and pedestrian path on its first day of operation, Sept. 3, 2013. Transit officials are exploring the option of creating a bike path that spans the entire bridge, from Oakland to San Francisco. less Cyclists ride by the Bay Bridge eastern span’s tower on the Alexander Zuckermann bicycle and pedestrian path on its first day of operation, Sept. 3, 2013. Transit officials are exploring the option of ... more Photo: Brant Ward / The Chronicle Photo: Brant Ward / The Chronicle Image 1 of / 8 Caption Close Plan for Bay Bridge bike path from Oakland to S.F. in high gear 1 / 8 Back to Gallery

The popular Bay Bridge eastern span bike path should finally reach Yerba Buena Island next summer, and now transportation officials are preparing to take it all the way to San Francisco.

Pushing the plan for a bike and pedestrian path on the western span into higher gear after years of pondering the project, a Bay Area Toll Authority committee voted Wednesday to pay a consultant up to $10 million to produce an affordable proposal that would pave the way for an Oakland-to-San Francisco crossing.

Bicyclists and pedestrians have long dreamed of being able to traverse San Francisco Bay under their own power. As it stands, it’s a choice of traveling across the bridge in a vehicle, under the bay in a BART car or across the water in a ferry.

Earlier estimates of the cost of a bike path, most likely attached to the sides of the approximately 2-mile western suspension span, placed the price at $400 million to $500 million. The toll authority considers that figure impractical given the amount of funding expected from toll revenues and state and local funds.

“It needs to be less than that,” said Peter Lee, a toll authority engineer who did not want to guess at an acceptable price tag.

The consultant, Arup North America, will spend about a year studying the feasibility of the western span bike path, coming up with as many as four designs and identifying possible funding sources. If the authority chooses to push ahead with the path plan, it would need to find an additional $10 million to complete environmental studies, which would take time given the western span’s historic nature.

Bike advocates and transportation officials have discussed a western span bike path for a decade, but it has always been considered financially out of reach. A 2012 study estimated the cost at a half-billion dollars for a pair of pathways cantilevered off both sides of the bridge’s upper deck. One path would be set aside for bicyclists and pedestrians, while the other would be reserved for Caltrans maintenance vehicles.

Because attaching two paths would increase the weight of the suspension span, causing it to flatten slightly, the study suggested replacing the bridge decks with lighter materials, which could push the cost to $800 million to $1 billion.

Lee said the original plan envisioned full lanes on each side of the bridge, and suggested that consultants could look at a scaled-back version.

Renee Rivera, executive director of Bike East Bay, said the study was “a crucial next step to get to a fundable plan for a west span path” and was confident the price can be pared down.

“We’re looking forward to the day we can ride all the way to San Francisco from the East Bay across both spans,” she said.

Kristin Smith, spokeswoman for the San Francisco Bicycle Coalition, said: “A bike path along the Bay Bridge would encourage more people to bike, which would reduce congestion on the street and overcrowding on BART.”

The bike path now stops just past the tall white tower of the new east span while segments of the old east span are demolished. That work should be done, and the bike path extended to Yerba Buena Island, by Labor Day, Lee said.

But bicyclists face a long wait before they’ll be able to pedal across the western span and into downtown San Francisco.

“Even if all the stars aligned,” Lee said, “it would still be years away.”