Truths, traps, and tactics concerning alcohol, other drugs and highway safety.

Ingestion of alcohol by pedestrians is an important factor in severe highway crashes, just as alcohol is important in the injury of drivers and their passengers. Blood alcohol concentrations below 50 mg per 100 ml (0.05 percent by weight) do not increase crash risk, but above that concentration the risk rises rapidly. Three distinct groups-problem drinkers (many of whom do not have blatant alcoholism), teenagers, and heavy social drinkers-make up the over-whelming majority of persons in alcohol related crashes, and countermeasures specific to each group must be applied and evaluated. Past and present countermeasures usually have not been adequately evaluated, or in some cases have been proven ineffective. Countermeasures aimed specifically at reducing losses in addition to those aimed at changing behavior are an integral part of any control program. Based on limited evidence, abuse of drugs other than alcohol, with the possible exception of amphetamines, does not appear to be a frequent cause of crashes, and extensive countermeasures probably are not warranted at this time.