The $2.5-million project came together in the past year to build a smooth connection from Market Street to northbound Polk Street by funneling bicyclists traveling against traffic onto a green bike lane that passes City Hall.
The city's Department of Public Works director Mohammed Nuru joined San Francisco Municipal Transportation Agency transportation director Ed Reiskin and San Francisco Supervisor Jane Kim to cut the ribbon on the lane as dozens of riders perched on bikes watched.
It's only two blocks. It's not the distance that makes it a big deal, but rather the extent city planners went to make it safe for bicyclists.
Meryl Klein's life took a detour after riding her bike to class one evening.
"A car cut me off turning right and I went into the front headlight of it, fell backwards and the next thing I remember, I was in an ambulance," Klein said.
There was surgery and rehab. But it just so happens that class was in government administration.
Klein went to work for the MTA in bike and pedestrian safety.
"When something happens that all of a sudden you don't feel safe getting around, it really wakes you up," Klein said.
That crash likely wouldn't happen today because bright green bike lanes now line much of Market Street and are physically separated from car traffic.
But there was a missing link until now. A two-block stretch of Polk Street that was one-way is now two-way for bicycles.
The new northbound bike lane is well-separated from the cars headed south and even has its own traffic lights.
It keeps bikes from having to go on the sidewalk or take busier streets like Van Ness.
"People who don't bike may not realize, your choices before this were quite miserable," San Francisco Bicycle Coalition Executive Director Leah Shahum said.
This newest bike lane is part of a larger vision for the city that's being championed by pretty much any cyclist who's ever been hit by a car. And by the way, there are lots of them.
"I got hit by a car while cycling and broke my hip," bicyclist Madeline Savit said.
The stories are everywhere. In Savit's case, this ribbon cutting is her first time on a bike since the crash.
"And the only reason I did it was because it's safe," Savit said.
She and others are standing behind Reiskin.
"Would you like to see more of this kind of work all over San Francisco?" Reiskin said.
He's backing the mayor's effort to fund more bike lanes by raising the car tax. They've got one vote.
"Now that you see it once, you want it everywhere," Klein said.
The lane opened in time for next week's Bike to Work Day, which San Francisco Bicycle Coalition executive director Leah Shahum said was a strict deadline that expedited the project.
Shahum said her organization has been putting pressure on city leaders to make a safe and legal bicycle passage into the Civic Center area.
"This is a safe, direct and comfortable link to Polk Street," she said.
Bike to Work Day is celebrating 20 years of promoting bicycling as an alternative, healthy commute method in San Francisco and the Bay Area on May 8.
Most of the funding for the new lane came from Proposition B, the $248-million Road Repaving and Street Repair bond, which San Francisco voters passed in 2011, and from the SFMTA's 2009 Bike Plan.
Bay City News contributed to this story.