Black Lives Matter protesters block San Francisco's Bay Bridge

Protesters with the Black Lives Matter movement blocked traffic on the westbound span of the Bay Bridge that connects Oakland and San Francisco as part of a long weekend of protests aimed at reclaiming Martin Luther King Jr’s legacy of radicalism.

Shortly after 3.30pm, a caravan of cars slowed to a stop on the five-lane bridge. Passengers in the first line of cars passed chains through their windows and locked themselves to both sides of the bridge, bringing all westbound traffic to a stop.

“Today is the day when we reclaim MLK’s radical legacy,” said April Thomas, who was chained between two cars. “I’m out here for Tamir Rice, Rekia Boyd, for my mother, myself, for Harriet Tubman.”

Dozens of protesters streamed out of cars and onto the roadway, chanting, singing, and erecting a banner reading “Black health matters”. One activist erected a wooden shrine bearing the names of victims of police shootings.

In a statement, organizers of the protest said they were shutting down the bridge to “to demand investment in the wellbeing of black people”.

While some angry commuters honked and, in a few cases, confronted the protesters, others leaned out their windows to take pictures of the spectacle.

Officers from the California Highway Patrol arrived soon after the blockade was in place. Wearing riot gear and carrying less-lethal weapons, the officers ordered onlookers back into their cars. About 4.15pm, the officers began cutting chains and arresting protesters. Some protesters passively resisted arrest and had to be carried to the side of the road.

According to organizers of the protest, 24 people were arrested in total. Traffic began moving again at 4.30pm.

The bridge shutdown caps off four days of protest in the Bay area, where the Black Lives Matter movement has been galvanized by the fatal shooting of Mario Woods by San Francisco police officers on 2 December 2015.

Cellphone videos of the shooting of 26-year-old Woods, who was black, were widely circulated on social media, prompting outrage in the city’s shrinking African American community. Malia Cohen, a member of the city’s Board of Supervisors, described the incident as an “ethnically diverse firing squad”, and several members of the board have called for a federal investigation by the US Department of Justice.

Woods was allegedly armed with a kitchen knife when he was surrounded by at least 10 police officers who say he matched the description of a suspect in an earlier stabbing in the neighborhood. Five officers opened fire on Woods, killing him.

Shortly after the shooting, San Francisco police chief Greg Suhr told a community meeting that Woods had extended his knife toward police officers, an apparent justification of the shooting. But additional video of the shooting obtained by John Burris, the civil rights lawyer representing Woods’ family in a federal civil rights lawsuit, appears to show that Woods’ arms were at his sides when officers opened fire.

The incident has touched off renewed calls for police reform and racial justice in a city that prides itself on its diversity and liberal politics.

Mayor Ed Lee, the police chief, and the police officer’s union have called for police to be armed with Tasers, which they say could have prevented the shooting. San Francisco is one of the only cities in the country where police are not allowed to carry electric stun guns, in large part due to widespread community opposition. The police commission, which sets policy for the department, has initiated a review of San Francisco police department’s use-of-force policies.

But for many, these measures are insufficient. On Saturday, activists held early morning protests at the homes of Lee and Suhr, calling for Suhr’s resignation, the firing of the officers involved in the police shootings, and the reduction of police budgets. Protesters have also demonstrated at the homes of the Oakland mayor and police chief, both the San Francisco and Oakland airports, shouted Lee off the stage at an annual Martin Luther King Day breakfast event, and picketed a local fast food restaurant where they say a black worker was fired unjustly.

“I love black people, and all people,” said Zach Norris, one of the protesters chained to the cars. “We consistently see black folk are criminalized and killed when they have mental health issues. We’re here to say healthcare not warfare.”