It all started with creating an image for BikeSalute.com. I made an image out of the first 267 photos I got. I was emulating the work of Jason Salavon. For the bike salute image, I wrote a little program in Processing. Later I rewrote it in ActionScript and made it work with Flickr sets.
The next step was to make an average out of consecutive frames of a video. Some early tests are here and here. I found out that it looks better if the camera is static. I added the trail to videos from YouTube that had a static camera: Example 1, Example 2. The next step was to shoot some footage myself.