Abstract
Unstable spacing between automobiles tends to affect efficient traffic flow adversely. Two experiments were undertaken to test the effect of two types of driver information displays /meters/ on vehicle spacing. The first meter showed the driver the actual distance between his car and the car ahead. The second meter showed the driver the algebraic sum of the distance between the two cars and their relative velocity. The latter display increased spacing stability. No marketable device has been designed. Actual spacing data were compared with theoretical curves obtained from standard car-following laws. A reasonable approximation was obtained.