Shadow Moire Hits the Streets

Sidney Guralnick, a professor of civil engineering at Illinois Institute of Technology in Chicago, has developed a moire topography system to eliminate potholes. Called the Automated Road Inspection System, or Aris, the instrument reveals ruts and roughness in pavement so road crews can target problem areas for repair before they form potholes.

A prototype version of Aris, produced with the support of the National Science Foundation and the US Federal Highway Administration, fits in an 8 3 7-foot trailer that is towed at up to 55 miles per hour. A high-intensity light and wire grating cast a moire pattern on the road surface, which a video camera records for later analysis. Guralnick said that because Aris is powered by a standard light source, it should be less expensive than available laser-based profilometers for road inspection.