SPECIAL STUDY
Adopted: February 22, 1980
FATAL HIGHWAY ACCIDENTS ON WET PAVEMENT-
THE MAGNITUDE, LOCATION, AND CHARACTERISTICS 
NTSB Number: HSS-80/1
NTIS Number: PB80-163744 
SYNOPSIS
The National Highway Traffic Safety Administration (NHTSA) has reported that an average of 5,681 fatal accidents occurred annually from 1975 to 1978 on highway pavement that was wet. This represented 13.79 percent of all fatal hihghway accidents. The National Safety Council indicated that in 1977, data from 23 States revealed that 13.9 percent of the fatal accidents, 19.4 percent of the accidents producing injuries, and 18.6 percent of the total accidents occurred on wet pavement. Since the total percentage of all accidents on wet pavement exceeds the percentage of fatal accidents on wet pavement, the use of fatal accident data conservatively represents the incidence of wet-pavement accidents. Because this report will explore whether there is a nationwide problem, only fatal accident data, which are the only all-inclusive data collected uniformly nationwide will be used.

Concern for the problem of accidents on wet pavement varies substantially among the States. A report on wet-pavement accidents that occurred in 1969 on the West Virginia highway system revealed that the average rate of wet-weather accidents was 2.2 times the rate of dry-pavement accidents and that the maximum rate was 85 times the dry-pavement rate. Forty percent of the accidents on the West Virginia interstate system occurred on wet pavement. The report estimated that the roads in West Virginia were not wet more than 15 percent of the time. If analysis of the national data reflects findings similar to those of the West Virginia report, the wet-pavement accident problem should be a major concern to all States; this study will analyze national data. The types f wet-pavement accidents that result in fatalities and the limited human data available will be discussed briefly. Finally, the report will describe the application of the methodology developed in this study to analyze the possible relationship of pavement design and aggregates to the incidence of fatal accidents.

RECOMMENDATIONS

As a result of this special study, the National Transportation Safety Board made these recommendations:

--to the Federal Highway Administration:

In conjunction with the National Oceanic and Atmospheric Administration, provide weather data to Federal, State, and local agencies, and promote and use these data to reduce accidents on wet pavement. (Class II, Priority Action)(H-80-21)

Promote further research into the relationship of wet-pavement accidents (1) to low void ratios in pavement surface mixes, (2) to highway construction materials, and (3) to artificial light conditions. (Class III, Longer Term Action)(H-80-22)

Test the use of the Wet Fatal Accident Index (WFAI) as an aid to identify and evaluate State programs aimed at reducing accidents on wet pavement. (Class III, Longer Term Action)(H-80-23)

--to the National Highway Traffic Safety Administration:

Develop a program to alert the public to the component factors and magnitude of the wet-pavement accident problem.(Class II, Priority Action)(H-80-24)