The three known ghost bikes installed in Philadelphia were placed by a group of volunteers one of whom told us
A few of us put the bikes together after a conversation about why there weren't any ghost bikes in Philly. The answer was, let's make them! A local bike advocate helped us get the junker bikes. The plaques were attached with nylon straps through holes we drilled out. The wood is some scrap plywood we found in the trash. [Sadly,] there were a handful of other bike deaths over the past couple of years, but they were harder to find information on.