Ehlinger said the accident occurred just 10 days after Doylestown's annual Ride of Silence, part of a worldwide event calling attention to cyclists killed by motorists each year.
"This does hit home," said Ehlinger.
Ghost bikes are white-painted bikes that are memorials for dead cyclists. First used in St. Louis in 2003, they are now in more than 150 locations around the world, according to the website ghostbikes.org.
Chapman, 66, a textbook writer who lived in the Queens borough of New York City, was among a dozen or so cyclists taking part in the annual trip, known as the New Hope Ride, that was planned by the Fast and Fabulous Cycle Club, a gay and lesbian club in New York.
After heading south through New Jersey, Chapman stopped in Lambertville, N.J., where he helped another cyclist fix a flat tire, and then crossed the Delaware into Bucks County, where ultimately the riders would spend the weekend at Lake Nockamixon before heading back to New York.
But about 4:30 p.m. on Saturday, May 28, as Chapman stopped to check directions on Route 413 near the border of Plumstead and Buckingham Townships, he was struck by a white pickup that sped away.
David Roycroft, a friend of Chapman's who was part of the caravan, said he had fallen a bit behind Chapman and was just catching up when he saw Chapman standing on the shoulder of the road looking at his cue sheet. All of a sudden, he said, he saw the pickup truck driving "erratically" in the direction of an oncoming vehicle and then swerve toward Chapman.
The driver was going about 60 m.p.h., Roycroft said, and knocked Chapman into the drainage ditch. "It just kept going. It didn't even slow down," he said.
Plumstead Township Police Chief Duane Hasenauer said police are looking for a 2003 to 2006 white Chevrolet or GMC pickup truck that left behind the passenger-side rearview mirror after the accident.
"Somebody out there has to know something," said Hasenauer, a bicyclist who said he has given up cycling on the roads in favor of mountain biking "simply because how many times I've been run off the road."
Terry W. Clemons, a Doylestown lawyer and longtime cyclist, said he was buoyed by the enthusiastic response to the reward fund, which he started with a $250 contribution.
"I think people ought to be aware of how exposed cyclists are out there to dangers of motorists and anger," said Clemons. "There's just so much anger and intolerance out there."
Chapman, meanwhile, was remembered at an impromptu memorial service the day after the accident at a church near Lake Nockamixon and again June 26 at a memorial service in Manhattan.
Friends described him as a joyful optimist and an enthusiastic cyclist who had done the ride in previous years.
"He was very excited about the ride," said Roycroft.
"Bucks County is so beautiful and the state park is so nice. It's just a wonderful place to spend the Memorial Day weekend."
Cyclists in Bucks County and New York said it was disheartening that any driver would take off after hitting a bicyclist.
Roycroft said he is hoping for justice.
"It is unbelievable - hard to imagine - that they wouldn't stop," said Roycroft.
Contact staff writer Emilie Lounsberry at firstname.lastname@example.org.