Analysis of effectiveness of longitudinal grooving against hydroplaning

Abstract

Longitudinal pavement grooving has been applied in highways to reduce the occurrence of hydroplaning at accident-prone locations. However, to date there has not been a systematic study of its effectiveness against hydroplaning. This lack can be attributed to the difficulty in conducting such experiments and the extreme complexity of the theoretical analysis involved. A numerical model was developed to simulate the hydroplaning phenomenon. Then a systematic study was conducted on the effectiveness of various designs of longitudinal grooving against hydroplaning. The analysis covers groove widths of 2 to 10 mm, groove depths of 1 to 10 mm, and groove center-to-center spacing of 5 to 25 mm. Groove dimensions were found to have significant effects on the effectiveness of a grooving design against hydroplaning. The results show quantitatively how the use of larger groove width and depth and smaller groove spacing reduces hydroplaning risk, by computation of the changes in the expected hydroplaning speed. For the range of groove dimensions studied, the expected hydroplaning speed for a typical passenger car increased by approximately 2.8 km/h for every mm increase of groove depth, by approximately 3.5 km/h for every mm increase of groove width, and by approximately 1.0 km/h for every mm decrease of groove spacing. The model also was applied to evaluate the hydroplaning potential of different grooving designs used in practice and past studies and to explain the conflicting findings of past studies on whether longitudinal pavement grooving does improve traction and reduce hydroplaning risk.