SAN FRANCISCO (CBS SF) — A new state law that went into effect this year will decrease speed limits to 20 mph for seven streets in San Francisco that go through business districts, Mayor London Breed’s office announced Thursday.

“We know that speed is the number one killer on not just San Francisco streets but California streets,” said San Francisco city attorney David Chiu.

The speed limits are being reduced on parts of 24th Street, Fillmore Street, Haight Street, Polk Street, Ocean Avenue, San Bruno Avenue and Valencia Street.

Uber driver Sahibou Oumarou drives the Polk corridor frequently and says he thinks speed limits should be even lower.

“This is the middle of the city. People shouldn’t be driving like crazy,” he said.

“I think it’s definitely necessary because cars do go fast here sometimes,” said Meg Leveen, as she walked her dog along Polk Street.

Pedestrian advocates with Walk SF, a non-profit group, say this small change can make a big difference.

“Every five miles per hour faster a driver is going, the less likely someone is going to survive in that crash,” explained Marta Lindsey, communications director for Walk SF.

Assembly Bill 43, parts of which went into effect Jan. 1, allows jurisdictions to lower speed limits by 5 mph in business activity districts, defined in the law as neighborhoods with at least half of the buildings along the corridor having commercial uses.

Some worry the reduced speed limits could lead to more traffic stops and potentially confrontational interactions between people of color and police.

“I’m kind of against it. It feels unsafe. It feels unnecessary and I don’t think it should happen,” said Jason Martin, who has lived in San Francisco for 20 years.

Crews this week have started installing signs with the new speed limits and city officials later this year will propose additional streets for lowered limits. The proposal would have to be approved by the San Francisco Municipal Transportation Agency board of directors.

Breed and other city officials said the move is necessary to improve safety on streets and is part of San Francisco’s Vision Zero goals to eliminate traffic deaths.

SFMTA director Jeffrey Tumlin said, “Speed is the leading cause of serious and fatal crashes in San Francisco, so reducing speeds is the single most effective tool for achieving Vision Zero. Just 5 mph can be the difference in whether someone survives a crash. Under AB 43, we’ll be able to set speeds that create safer conditions for all along these key corridors.”

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