After visiting a friend in the hospital twice -- for two bike crashes in the course of a single year – Dave Brindley was moved to action.
The West Philadelphia resident figured he could do something, at least, about the most dangerous spot on his morning commute, the 3700 block of Spruce Street. There's a bike lane, but there's also a corner Wawa and a wide shoulder that tempts a constant stream of motorists to park, forcing cyclists to swerve into traffic.
Brindley, 37, set about gathering stray traffic cones left by Verizon, PGW, and the Philadelphia Water Department, and set up a makeshift protective barrier.
"I had no idea if it would be there the next day or not," he said. "But it's been two years. By now, the police think it's theirs."
This low-tech intervention represents one of the more successful examples of a national movement by pedestrians and cyclists who have tired of waiting for local governments to make what they view as necessary infrastructure upgrades.
Sometimes called "tactical urbanism" (and other times called "vandalism"), guerrilla engineering projects have included spray-painted bike lanes in New York and Los Angeles, DIY crosswalks in Baltimore, and a protective buffer of potted plants along a bike lane in Boston.
Here in Philadelphia, projects have been scattered, and stealthy.
A pair of artists, laid low one too many times when their bicycle wheels were caught in the grooves of disused trolley tracks, filled in the tracks themselves during a grueling week of midnight roadwork.
The Bicycle Coalition of Greater Philadelphia has given cones to Trader Joe's to protect the 22nd Street bike lane whenever the supermarket's parking-lot overflow creates a hazard.
And then there's Brindley, who has extended his amateur traffic engineering to a couple of sites, with mixed success. (A campus minister based at the University of Pennsylvania, he doesn't worry too much about the legality. He cited a higher authority: "I believe God cares for humanity.")
He sees the projects as demonstrations: It's up to the city to make them permanent.
Kelley Yemen, the city's complete streets coordinator, rejected the idea.
"We welcome continued discussion," she said, "but we don't want people putting up cones or making their own traffic changes, as it can create an unsafe environment."
Still, to some cyclists, those discussions can seem interminable.
The city in March won a $300,000 grant to install protected bike lanes, but at a meeting in November -- the first of many to be held around the city -- Jeanette Brugger, a city planner, assured members of the Washington Square West Civic Association that no sites had been selected.
"We're aware," she said, "we need to do a lot of outreach before this goes forward."
Residents, concerned that the bike lanes on Spruce and Pine Streets would be lined with barriers, cited numerous drawbacks. One said, "We're a historic neighborhood." Barriers would be "a visual intrusion."
Another, Jonathan Broh, president of the civic group, said the barriers would prevent ambulances from navigating traffic jams.
"I want better bike lanes," he said, "but not at the expense of someone in the back of an ambulance having a heart attack."
On the other hand, Megan Ryerson, a professor of transportation and city planning at Penn, said she felt unsafe maneuvering around all the parked cars on Spruce, particularly with her young twins on her bicycle. For an ambulance to be stranded would be terrible, she said, but added, "I've seen so many bicyclists hit in a bike lane. That's also a terrible thing."
Randy LoBasso, a Bicycle Coalition spokesman, said many constituents expressed frustration about the sluggish pace of progress.
Consider Katie Monroe, a former Bicycle Coalition staff memberer who broke her jaw when her tire was caught on the Route 23 tracks on 11th Street, where no streetcar had run in more than two decades. It took her three years of lobbying just to get the city to remove the section of track that took her down, at 11th and Reed Streets.
By contrast, artists Jared Dyer, 28, and Gabriel Slavitt, 27, filled in half a block of defunct track farther north on 11th Street in less than a week.
Both now live in Los Angeles, but in 2013, they were working out of an art space near Chinatown. They'd read that removing the old tracks would cost millions of dollars. They decided to see what they could do for $100.
So, partly as a gift to Philadelphia cyclists, partly as conceptual artwork, they embarked on a project titled To Make a Safer Block.
They bought asphalt, made their own tamping tool, and set out at 2 a.m. one summer night to do the work.
"We tried to do it like we assumed the city would do it, or better," Dyer said.
They completed half a block's worth of tracks, then ran out of money. They figured at least that one patch of tracks was now safer for cyclists.
"It was a project proposal more than anything else: If we could all do this, what would it be like?" he said. "The intention was to present a possibility for a bigger conversation."
That conversation is happening now in cities around the country.
In San Francisco, a group of anonymous activists, galvanized this summer after two deadly bike crashes there, have protected 0.18 miles of bike lanes with cones and official-type flexible barriers. The city allowed at least one section to remain in place until a permanent fix could be implemented.
Michael Lydon, a New York planner and author who wrote the book Tactical Urbanism, said governments' responses to such initiatives were evolving.
"As of late, we're seeing some cities move forward with programs and policies that enable this work to happen from the bottom up, instead of being caught flat-footed," he said.
His advice to prospective DIYers: Start small and temporary, and make sure your intervention isn't creating a new problem for another road user. A good place to start is a project that's part of a city plan already, but hasn't been implemented.
Brindley figures the city intended a bike lane on Spruce Street, but didn't maintain it: The white stripe has partly worn away.
Now, he thinks the intersection – the fourth-busiest in the city for cyclists, according to the Bicycle Coalition – deserves professional attention.
"University City deserves a more elegant solution than I can give it," he said.
In the meantime, he has moved on to other projects. Last year, he set out cones on what he calls a "death trap" on the 3200 block of Chestnut Street, where cars often park in the bike lane. (Drexel police took them down after a week, he said.)
And he's launched Not in Philly, which he says is the first map-enabled, adopt-a-block website in the country, to tackle Philadelphia's litter problem.
He hopes his work will have a ripple effect.
"Maybe I can inspire other citizens to think about what they can do to make their city a safer and better place -- even without waiting for the city bureaucracy to work its way through."
But, he added, "there's a limit to what one guy with cones can do."