For Boston cyclists, Massachusetts Avenue can be a terrifying place to ride–drivers routinely ignore the stripes marking the bike lane and swerve into the path of bikes. After a truck driver recently killed one young bike commuter , the city promised to add some simple barriers to the lane. But they were slow to act.

So another bike commuter decided to take on the problem himself: On his way to work in Harvard Square, Jonathan Fertig dropped off a line of orange construction cones and potted flowers along the edge of the bike lane.

“I’ve been growing increasingly frustrated over the past year,” says Fertig, who saw progress on bike infrastructure in the city start to slow when a new mayor came into office.

“When a young woman was killed by a truck driver last month while riding the route that I ride every day it hit me in an unexpectedly personal way,” he says. “I was searching for a way that I could do something to amplify to fury that many of us in the walking and cycling advocacy community were feeling.”

He picked up a copy of Tactical Urbanism, a book that lays out urban interventions like DIY bike lanes. Inspired, he “just decided to drop some cones in the buffer of the newly installed bike lane. In an instant, cars were no longer using the bike lane as a turning lane.”

The flowers have a symbolic connection to the memorial at the corner, where a ghost bike has a flower-filled basket. “Flowers are also beautiful and entirely non-confrontational in their own right,” Fertig says. “I liked the concept of using them in an act of civil disobedience. … I am a child of hippies, after all.”

The intervention worked–at least for a small stretch of the road. “It’s a joy for 200 feet, until you reach the corner where the terror resumes,” he says. “I’ve had countless people tell me online that the intervention made a big difference.”