I love this concept.
"Conceived by Pepin Gelardi and Teresa Herrmann, this frame-mounted device would allow cyclists to make their mark on the street with faint lines of chalk. The rear wheel spins a smooth trail of color onto the pavement as the bike whizzes along."
Wouldn't it be great if we could get every cyclist in the area to have one of these on their bikes. People could start to see how often people use their bikes and where they ride.