The bike sits perched atop a mound of ice in Minneapolis’ Loring Park, its front wheel raised in a permanent wheelie. Fresh, snow-white paint covers a simple, bare-bones frame.

Although it hasn’t been abandoned, this bike has no rider.

It’s a ghost bike — a roadside memorial marking the site where a cyclist was killed.

The bikes started appearing around the Twin Cities several years ago, next to major thoroughfares, near busy intersections, even along quiet stretches of road. Sometimes they’re adorned with flowers, photos, handwritten notes and the name of the rider. Others are starkly anonymous. A few have been the touch point for memorial marches and rides.

But almost all of them appear quietly, usually overnight, and disappear just as quietly.

“The nature of ghost bikes is that people aren’t even sure who puts them up,” said Garrick Yoong, a Minneapolis cyclist who has helped install a few of them.

A ghost bike commemorates Dennis Dumm, who was killed in 2009 at the intersection of 14th Street and Park Avenue S. in Minneapolis.

Even though Minneapolis has a ghost bike archive (www.ghostbikempls.org) similar to an international site (www.ghostbikes.org), no individual or group claims responsibility for assembling and installing them. Even people in the tightly knit cycling community rarely know who’s behind a bike, partly because those who are don’t want to take the credit.

“It’s not done for any other purpose than to mourn the cyclist who died,” said Danny Gamboa, a Los Angeles-based filmmaker who’s working on a feature-length film about ghost bikes.

“We let the community know that the collision happened.”

Yoong said ghost bikes often come about organically. They typically appear after high-profile fatalities like hit-and-runs, said Gamboa. Typically, cyclists check Facebook to see if a ghost bike has been installed. If not, a few cyclists will get together and put up a ghost bike. Sometimes the deceased’s family will put up their own.

The bikes typically are donations, junkers or built quickly from spare parts. They don’t even need to be fully functional.

“Parts aren’t a concern,” Yoong said. “The main thing is that it’s recognizable as a bike.”

Once assembled and painted white, they’re locked (often with a white chain) near where a cyclist was hit. Many of the bikes aren’t recorded on the registry, so no one knows how many have been put up around the Twin Cities.

James McDonald, owner of Sunrise Cyclery, said his used bike shop in Minneapolis has donated three bikes to be made into ghost bikes this year already.

Most ghost bikes face an uncertain future: Some are stolen, some are adopted by other riders, some are removed by the municipality.

Kevin Kirsch, a volunteer with the Minneapolis Bicycle Coalition, has taken on the task of maintaining the ghost bike for Jessica Hanson, who died last summer after being struck by a hit-and-run driver at 28th Street and Pleasant Avenue S. Kirsch never knew Hanson, but rode by her ghost bike one day. “It looked so sad,” he said. “I couldn’t let it sit there.”

Since then, he and a few friends have shoveled the snow around the bike. He’s also gotten to know Hanson’s family. In fact, Hanson’s mother asked Kirsch to give a victim impact statement to help show how Hanson’s death affected the community.

However, not everyone appreciates the wheeled memorials.

Tom Paddock, an evidence technician with the city of Minneapolis, said there are numerous, and sometimes inconsistent, laws that affect how the city responds to ghost bikes. Historically, the city has dealt with ghost bikes, as with other roadside memorials, on a case-by-case basis.

But the rules only come into play when a municipality notices a ghost bike, which may not happen unless a resident files a complaint.

“From what I’ve noticed … [ghost bikes] are being taken down after a year or a year and a half,” said Melody Hoffmann, who has been biking in Minneapolis for 10 years.

Not everyone appreciates ghost bikes.

Candles and flowers helped mark the spot where Tim Malloy was killed in 2011 on West River Road.

Kirsch said he’s had run-ins with a neighbor who asked him to remove the Hanson ghost bike.

“It’s hard to be reminded [of death] every single day,” he said.

Still, he’s trying to get the neighbors to “embrace it.”

“If I can keep [Hanson’s] story visible and alive, maybe this dangerous street will change,” Kirsch said. “Maybe those who see the ghost bike will slow down.”

Eric Best is a University student reporter on assignment with the Star Tribune.