Citation

Zipkes E. Transp. Res. Rec. 1977; 623: 70-75.

Copyright

(Copyright © 1977, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Frequency of accidents and the percentage of accidents on wet and dry road surface for the years 1966 - 1973 have been analysed on a road of 44 km, comprising few very smooth spots on a total length of about 2 km. Data for analyses vere provided by official traffic counts, precipitation measurements of the Swiss Central Meteorological Agency and accident report of highway police. The 2 km long smooth sections have been grooved twice during the observation period with groove distances of 5,0 and 2,0 m. This road represents a good example for a study on the influence of grooving on accident frequency. Relative values of accident frequency per km and 1 million vehicles were determined in relation to the number of wet and dry days of each year, for the grooved and ungrooved section. The percentage of accidents on wet surface compared to the total number completes the study. The results show clearly a positive influence of grooving, even with great groove distances, and the effect of a reduction of the water film on skidding properties. A clear-cut information is given particularly by the relation of accidents according to the formula: A sub N = A sub W/A sub w+d 100 (%). Economical aspects of this measure and legal questions about the road owner's responsibility are also considered.