Comparing Spray from Tires Rolling on a Wet Surface

ABSTRACT Tire spray generated as automobile or truck tires roll over a wet roadway is a familiar hazard to all drivers. Past efforts to mitigate the effects of tire spray have focused on inventing and testing add-on devices to suppress, redirect, or contain spray. These devices have had only limited success in controlling spray. An alternate approach would be to examine tire spray at the source—the tire and wet roadway. This article describes a device designed to simulate tire spray in a laboratory setting, allowing a careful examination of spray in a controlled environment. The device limits the spray to that produced from water passing through a tire groove and then carried away from the roadway by the rotating tire. The spray pattern downstream of the tire patch is captured with high-speed video and stored on disk. The video images are then processed as desired by computer. A concept “time-to-drain” is introduced to characterize the angle at which spray leaves the tire. Time-to-drain is then used to compare the spray patterns of different tires.