"I'm concerned that it will confuse the issue and create even greater misunderstandings between cyclists, drivers and pedestrians," said Cohen.
Officials from the San Francisco Department of Public Health and the San Francisco Municipal Transportation Agency also expressed reservations. A health department official said there was a lack of evidence the proposed policy would help reduce injuries and fatalities, while an SFMTA official said it could "send an ambiguous signal to road users we might be removing predictability from the roadway."
But Supervisor John Avalos stressed the law is about focusing enforcement on dangerous behavior. He said he's amended the ordinance to address concerns from disability and pedestrian advocates, and has also tacked on an education campaign component.
"This is really about focus, defining what yield and safe bicycling is so law enforcement can focus traffic enforcement on the most egregious behaviors," said Avalos.
Supervisor London Breed, who is co-sponsoring the legislation, agreed that limited police resources should "be used for more important things."
"I personally witnessed crackdowns that I thought were just unfair and unjust. They involved people along The Wiggle who were clearly biking safely," said Breed.
It's still unclear whether there are 11 votes to override a threatened mayoral veto. Supervisor Mark Farrell has said he is likely to support the legislation. Supervisor Katie Tang and Supervisor-elect Aaron Peskin have not indicated how they plan vote.
A proposed law that would require San Francisco police to make ticketing bicyclists who roll safely through stop signs their lowest enforcement priority faces a crucial test at City Hall this afternoon.
The hearing before the Board of Supervisors Land Use and Transportation Committee comes as police confirm that officers have resumed beefed-up enforcement of bicyclists along The Wiggle, one of the city's most popular bike routes.
Advocates with the San Francisco Bicycle Coalition have decried the ongoing crackdown as an unnecessary use of police resources and say the focus should be on dangerous drivers who cause the majority of collisions involving severe injuries and deaths.
Police had pledged to focus on the five most dangerous driving behaviors as part of the city's Vision Zero campaign to end all traffic deaths. Capt. John Sanford, head of Park Station, which oversees The Wiggle, has said the enforcement against bike riders is largely driven by complaints.
Andrew Stoltzfus, a bike coalition member who commutes along The Wiggle, recently submitted a public records act request and discovered police dedicated 114 enforcement hours during a two-day crackdown in August. But he found no records for July or August of enforcement at the city's most dangerous intersection for bicyclists: Market and Octavia streets.
"I think what the Police Department is doing is looking for where they can get tickets, but also just blindly reacting to the most vocal citizen complaints," said Stoltzfus.
In a letter to the land use committee opposing the proposed law, Police Chief Greg Suhr released collision numbers for the first nine months of 2015, which he says show bicyclists were at fault in 46 percent of collisions with motor vehicles. The letter also said bicyclists have been found at fault for a substantial share of the collisions involving stop-sign violations over the last several years:
From January 1, 2010, to December 31, 2014, bicyclists have been at fault for 30 percent of the collisions resulting from a failure to stop at a stop sign in violation of CVC §22450(a); that equates to 129 of the 427 injury and fatal collisions during that time period. In the first nine months of 2015, January 1 through September 30, there have been 447 collisions between bicycles and motor vehicles, including two bicycle fatalities. The driver of the motor vehicle was at fault in 216 (48 percent) of the incidents, the bicyclist 206 (46 percent) of the total, and 25 (6 percent) incidents are unknown.
"It is unacceptable to encourage someone to break a law that could result in injury or death because it is 'inconvenient' for the driver/bicyclist to come to a complete stop," Suhr wrote.
Safe streets advocates point out that the data cited by Suhr do not focus on what kind of behaviors are causing the most severe injuries and deaths. Previous numbers cited by the city say drivers caused 65 percent of fatal collisions from 2008-2012.
The 2010-2014 police numbers show drivers who failed to stop at a stop sign were at fault in a majority of the collisions: 70 percent. Advocates say it appears most cyclists who caused collisions during that time frame appear to be, for the most part, injuring themselves.
Stoltzfus said he is deeply skeptical of numbers released by the department, considering SFPD's troubling history of blaming bike riders in collisions. His colleague Amelie Le Moullac, was killed by a truck driver while riding her bicycle in 2013. SFPD initially faulted her for causing the collision until an advocate uncovered surveillance video that showed the driver was at fault. The driver never faced criminal charges, but was found negligent by a civil jury.
"They have a reputation and a history of always assuming the bicyclist is at fault until they are proven with evidence otherwise," said Stolzfus.
Bike advocates say most cyclists safely maneuver through intersections without coming to a complete stop. They say that in other cities where bike yield laws have been adopted, there has been a decrease in collisions involving bicyclists.
Mayor Ed Lee has threatened to veto the legislation, telling reporters in September: "I’m not willing to trade away safety for convenience, and any new law that reaches my desk has to enhance public safety, not create potential conflicts that can harm our residents."
The Mayor's Disability Council has also come out against the proposal, in a letter to the committee, according to the San Francisco Examiner:
"As it is today, some bicyclists consistently run red lights and fail to stop while pedestrians are in the intersection with the right of way,” the letter said. “Giving bicyclists permission to use their best judgment rather than following clear traffic laws would only make matters worse.”