To San Francisco cyclists, the blocks that ripple out from the downtown Caltrain station at Fourth and Townsend streets are a galling illustration of the city’s inability to smooth their path and protect them.

Bike commuters traveling to Caltrain or AT&T Park have to pinball around Muni buses, taxis, Uber and Lyft cars, and traffic spilling in from Interstates 80 or 280. They hit pavement riddled with potholes and are forced to veer around drivers parked in the bike lanes, which are marked by white paint but lack safety barriers.

Those road hazards — and dozens of cyclist-involved accidents — have led city officials to designate the Townsend Street corridor between Fourth and Eighth streets a high-injury area for cyclists. From 2012 through 2016, the San Francisco Municipal Transportation Agency logged 44 collisions involving cyclists on that stretch of roadway. None of them was fatal.

“The road is poorly paved ... and overrun by cars,” said bike activist Kyle Grochmal. “And then you see people pulling in and out of bike lanes with no regard for cyclists.”

In April, SFMTA released plans for a protected bikeway along the Townsend Street corridor, a solution that the bike community embraced. It would include a curb or barrier to separate bikes from traffic between Fifth and Eighth streets, and a strip of sidewalk in front of the Caltrain station.

But this month, the agency put the project on ice. Officials said they wanted to wait and incorporate the bikeways into the long-planned extension of Caltrain to the downtown Transbay Terminal, which won’t break ground for at least five years.

Cyclists are livid.

“We know this street is (potentially) deadly, and we can’t wait an undetermined number of years to fix it,” said Matthew Brezina, an avid cyclist who lives in Noe Valley.

Bike advocates cite the retreat from the Townsend Street bikeway project as an unsettling example of city officials’ reluctance to create protected bike lanes, which often meet resistance from merchants, community groups, the firefighters’ union and even the SFMTA itself.

The agency put the project on hold after estimating that it would cost $6 million to shift parking lanes and reposition overhead bus wires to accommodate safety measures that would be in place for a relatively short time. The work would have to be redone once the agency starts digging up the streets to make way for the Caltrain extension.

Brezina and others aren’t buying it.

“The safety of people biking down Townsend Street can’t wait five or 10 more years,” said Brian Wiedenmeier, executive director of the San Francisco Bicycle Coalition.

In the meantime, SFMTA staff will consider making small upgrades between Fifth and Eighth streets, which may include bike lane barriers, said spokesman Paul Rose. But the agency hasn’t committed to anything.

Blocks away, cycling advocates are fighting another battle over a stalled bikeway project along the Embarcadero, where cyclists and pedicab drivers weave dangerously among taxis, cars and tour buses. This month, a pedicab operator was struck on Embarcadero near Sansome Street by a gold Honda sedan whose driver fled the scene. The pedicab operator died Monday night.

The death of 66-year-old Kevin Manning jolted the city, provoking immediate calls for action. It cracked open a debate that had stewed for years between the SFMTA, neighborhood groups, merchants and the city’s port, which owns much of the Embarcadero property.

In a statement on behalf of the SFMTA, Rose expressed “deep sympathies” to family and friends of Manning. He said the agency will announce a final design for the Embarcadero this fall, and that it would feature a two-way protected bike lane.

Neighbors had pushed back on the idea since its genesis in 2014. Troy Campbell, executive director of the Fisherman’s Wharf Community Benefit District, recalled community meetings in which merchants, landlords, longshoremen and area residents expressed various concerns.

“Loss of left-hand turn lanes, deliveries, ride-shares, access, how to deal with certain intersections, such as where the F line crosses at Pier 39 — there’s just so many pieces to it,” Campbell said. Nobody objected to bike lanes per se, he said; the question was how to implement them.

Other safety-improvement projects have drawn objections from the Fire Department, which delayed construction of a protected bike lane on Upper Market for nine months, saying it would interfere with ladder trucks. The lane was finally completed in April, yet similar disagreement has stymied plans for bike lanes on Howard Street.

To San Francisco’s growing ranks of bicycle commuters, bikeways constitute an urgent need.

Manning’s death hung heavily over a group of bike activists who gathered Tuesday night to form a “people-protected” bike lane along Townsend Street between Fourth and Fifth streets.

Wearing bright yellow T-shirts and waving pink signs with plaintive messages — “Kids bike here,” one sign said — participants lined up along the bike lanes at either end of the roadway. Muni buses clattered by as Uber and Lyft cars swerved around the group to pick up passengers.

“I’m appalled — this traffic is crazy,” said John Entwistle, a bike activist from the Castro.

Laura Joosse said she dodges those traffic snarls every day as she rides a bike to her job near Union Square. The bike lanes on Townsend are so clogged with cars during rush hour that she prefers to use regular traffic lanes.

“There’s just so many people pulling over, dropping their families off at the station or stopping at corners,” she said.

The street draws scores of bikers each day, some of whom bring their bikes on Caltrain and commute to jobs on the Peninsula. Others park their two-wheelers at a valet bike station next door to the terminal. Still others rent Ford GoBikes from a large dock nearby.

Counterintuitively, the whole block is awash in bike infrastructure, though it’s treacherous for riders, Entwistle said.

“Look, they have all this,” he said, pointing to the garage-like station and the turquoise GoBikes locked in their individual berths. “They just don’t have beautiful bike lanes to complement it.”

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com

Twitter: @rachelswan