Abstract
An examination of accident patterns and traffic patterns for the republic of ireland for the years 1968, 1969 and 1970 shows that the risk of an injury accident is (a) twice as great during evening hours (6 p.m. to 11 p.m.) as compared with daytime hours ( 6 a.m. to 6 p.m.). (b) over seven times as great during the hour ending at midnight compared with daytime hours. (c) over four times as great during night hours (midnight to 6 a.m.) as compared with daytime hours. There are many reasons why the risk of accidents should be greater at night. The three which seem most important are fatigue, darkness and consumption of alcohol. The information given here suggests that alcohol is the predominant factor.