It doesn't cost much to make a stripped-down white bicycle to leave as a memorial near the spot where a rider died.
The bike is free. The spray paint costs maybe 98 cents a can, three or four of which will cover a bike. Pulling off the bike's chain, its brakes, its pedals, flattening the tires or filling them with concrete so there is nothing of worth to steal -- those take little energy. What is left is pristine and ethereal. Clean.
The lives the ghost bikes represent, however, are not cheap. Not to Nick Drombosky. In August 2009, the 23-year-old made the first such memorial, called a ghost bike, that the city had seen since 2004, and he locked it to a utility pole near the University of Pittsburgh at the tight, busy intersection of Meyran Avenue and Louisa Street.
It is a quiet reminder of Rui Hui Lin, a 38-year-old take-out delivery rider whom a driver hit there. Mr. Lin died after he was taken to the hospital. His death was the first in Pittsburgh of a bicyclist hit by a vehicle since 2004. Mr. Drombosky also made the signs that accompany the bike and tell only a little of Mr. Lin's story -- father of two, bicyclist, dead.
"It's such an odd thing to do," Mr. Drombosky said. "I know that. For a stranger to care about someone or an event they had nothing to do with is odd in our society. But I feel like it shouldn't be."
Mr. Drombosky is a cyclist himself, the kind who often leaves a pants leg rolled up to avoid catching it in the chain even after he's arrived at his destination. Adopted from South Korea at 6 months old, he grew up with a Polish family in Monroeville.
He made the first ghost bike on his own. Then two more this year with others, one for Donald Parker, killed in May in Indiana Township, and another for Albert Varacallo, who died in July in DuBois in Clearfield County.
"I didn't know how it was going to be perceived by the community," Mr. Drombosky said. "I didn't know how it was going to be perceived by law enforcement. I didn't know how it was going to be perceived by the families."
But he felt he had to do something.
"You can look at this and say it's just about bikes, but it's not," he said. "It's about people."
The first ghost bike Mr. Drombosky got from his roommate. The rest come from Free Ride, a bicyclists cooperative in Point Breeze. There are no rules about who gets a ghost bike. It happens only when it feels right and someone volunteers.
Rob de la Cretaz, 24, who became a regular cyclist after he moved to Pittsburgh from New Jersey in 2008, also has been moved to become an activist.
"Something about needless death really bothers the hell out of me," he said.
He got involved making ghost bikes after the one for Mr. Lin.
Not every fatal bike accident is memorialized. That includes one of a young man riding in the South Hills. "He's going the wrong way down a one-way street, no helmet on, ran a stop sign into a busy intersection," Mr. de la Cretaz said. "Maybe it's kind of cold -- he showed no obvious concern for safety. There's no ghost bike for him."
Contrast that with Mr. Parker, the cyclist who died in Indiana Township.
"He should absolutely be alive," Mr. de la Cretaz said. "He did everything right. That's something we want to memorialize."
Mr. Parker's mother, Aleen Croyle, said she learned of the ghost bike for her son the day after Mr. Drombosky and others held a memorial service and placed it on Hart's Run Road.
"It was such a wonderful thing," she said. "It's so important to remember him. It's a great honor, but it's hard knowing what it means."
PennDOT removed it after fewer than three weeks.
"There has been some talk of replacing it," Mrs. Croyle said. "But I don't know. I would like it but my daughter-in-law -- Don's wife -- said it's just too difficult having to drive by it all the time. It would be too hard for her to see it regularly. I respect that."
PennDOT's Pittsburgh-based spokesman, Jim Struzzi, said the agency respects what the memorials mean to families.
"By policy, you're not allowed to post any signs or leave anything in a public right-of-way without checking with us first," he said.
If PennDOT gets a complaint about a ghost bike, he said, someone will go look at it and make a decision. If it creates a distraction for drivers, Mr. Struzzi said, such a memorial could be counterproductive.
"You don't want to create a dangerous situation," he said.
With Mr. Parker's ghost bike, PennDOT acted on a complaint, he said.
"We simply took it to our nearest PennDOT facility and let someone come pick it up," Mr. Struzzi said. "We don't destroy it or anything."
The ones that remain will be maintained. New paint now and again, flowers in the summer. At least that's the plan.
"We want them to be there a long while," Mr. de la Cretaz said.
The first ghost bikes in Pittsburgh appeared one night in May 2004 around Allegheny County, placed where bicyclists had been injured or killed. It was a statement of protest, art and activism.
There were 13 or 14 of them, painted white and mangled.
"I put one out for myself where I got hit and broke my leg," said Eric Boerer, 33, who helped make and distribute them. Making the ghost bikes was cathartic in more ways than one.
"It felt good what we were doing," he said. "But we mangled them ourselves. Got hammers and wrenches and jumped on them to bend the frames. It was kind of fun, actually."
And then they were gone.
"The city, PennDOT, whoever, was really quick to pick them up," Mr. Boerer said. "Most of them lasted maybe a day and a half. But they got a lot of attention. And that was kind of the point."
Known almost universally in Pittsburgh's cycling community as "Erok," Mr. Boerer is now the advocacy and communication director for the nonprofit Bike Pittsburgh, which has nothing to do with the ghost bikes.
Pittsburgh was the second city in the country -- after St. Louis -- where ghost bikes appeared. They have since spread to 93 American cities in all and 22 other countries.
One cyclist who has studied the phenomenon is Zack Furness, who grew up in Pittsburgh and is the son of the late Steelers defensive tackle Steve Furness.
A doctoral student at the University of Pittsburgh in 2004, Mr. Furness the next year finished his dissertation, " 'Put the Fun Between Your Legs!': The Politics and Counterculture of the Bicycle."
Now an assistant professor of cultural studies at Columbia College Chicago, he expanded on the idea behind his dissertation in a book published in May, "One Less Car: Bicycling and the Politics of Automobility."
The seed for his research began while riding his bicycle in Pittsburgh in 1999, wondering why there was not more room for him on the road.
"Basically, this was the reality but what else could be possible," he said.
Ghost bikes fit neatly into the history of protest and advocacy among bicyclists, he said.
In Amsterdam in the 1960s, a group called Provo agitated for public bicycle-sharing, where riders would use a bike for a trip then leave it for someone else. The next decade in Montreal saw protests where bicyclists would surround themselves on the road with boxes the size of cars and close down intersections they would then fill with bicycles and bicyclists, asserting shared ownership of the road. Then riders in San Francisco began celebrating "parking day," plugging coins into parking meters for the maximum time and laying down sod and small trees.
"There was a lot of humor and a lot of creativity," Mr. Furness said. "The people doing the ghost bikes are sort of in the same tradition in a more somber way."
Meaghan Wilbur began documenting New York City's ghost bikes in photographs in 2008 after a friend died riding. The project grew into a documentary film, which she just started editing. She visited Pittsburgh for the placing of the ghost bike for Mr. Parker.
"I hear a lot that it's just activists co-opting people's deaths to make a point, but that's not really true," she said.
Most jarring to her, she said, is animosity toward riders.
"There is sometimes this blanket hatred of cyclists in a way that doesn't exist for careless drivers," Ms. Wilbur said. "I hear people say that people riding in the road deserve to die. I hear that a lot. That's really horrible.
"This is a life you're talking about."
Ghost bikes and memorial rides only accomplish so much.
Mr. de la Cretaz and Mr. Drombosky are among a group of people organizing a nonprofit called Flock of Cycles. This group aims to promote safe road use by increasing public understanding to the presence of cyclists on the roadways, and encouraging responsible cycling through education.
Mr. de la Cretaz said his passion for riding and evangelizing safety comes in part from his being a driver as well.
"I know how oblivious people can be to someone on a bike."
Jacob Quinn Sanders, a Pittsburgh freelance writer, also writes a food blog, www.eatsburgh.com.