Last weekend in San Francisco, bike advocates formed a human chain along the Embarcadero. They were calling for physical protection of a green bike lane that directly abuts high-speed traffic — using their bodies to shield the riders who use the route every day.

It was the third such protest in San Francisco in recent months, and it’s a tactic that’s inspired advocates in other cities.

New York City’s Transportation Alternatives organized a human-protected bike lane protest along Second Avenue in Midtown Manhattan, which lacks physical protection during the morning rush hour (at other times there is a row of parked cars). With nothing to stop them, drivers park and obstruct the bike lane, forcing people on bikes out into moving motor vehicle traffic.

To show the need for round-the-clock protection, about 45 people held hands and cheered everyone riding down the bike lane on their morning commute, documented by Streetfilms: