Back in 2004, Bikes Against Bush created a mobile bicycle-based chalk printer to print messages on sidewalks. The bike had a large dot-matrix printer on the back, designed to print messages as the bike rolled along sidewalks.

When cars drive over roads, any grooves or bumps can vibrate the tires at a desired frequency, depending on the car's speed and the spacing between bumps. You might recall the safety grooves etched in the sides of highways, or near intersections that warn for an approaching decrease in speed.

In japan, the 'singing roads' project encoded songs into the roads. likewise, the 'road tunes' HB idea records roads as grooves.

However, these require expensive grinding equipment, and the grooves are relatively permanent. A printer that applies tar or fast-curing epoxy to the road surface in a similar pattern could print song messages or maybe even crude speech reconstructions more cheaply, instead of cutting material out of the road surface.
-- squirrelecule, Aug 07 2010

Bikes Against Bush http://www.bikesagainstbush.com/blog/
printing messages from bike on sidewalk [squirrelecule, Aug 07 2010]

Road tunes Road_20tunes
[squirrelecule, Aug 07 2010]

SINGING ROADS - TAKE A MUSICAL TRIP IN JAPAN http://www.youtube....watch?v=yTsoP3WWgU4
[squirrelecule, Aug 07 2010]

random, halfbakery