Police perception of intoxication among injured pedestrians.

To assess police officers' accuracy in perceiving alcohol or drug intoxication of injured pedestrians, blood test results from pedestrians struck by vehicles and admitted to a Level I trauma center for a 3-year period were linked to police reports of the crashes. Police officers were 64.5% sensitive and 99.3% specific in identifying alcohol use in injured pedestrians when blood tests were positive for alcohol, and 2.2% sensitive and 100% specific in identifying other drug use when blood tests were positive for drugs other than alcohol. Those with higher blood ethanol levels were more often correctly assessed to be under the influence. Injury Severity Score and the presence of head injuries had no apparent effect on police assessments. In conclusion, police assessment of substance abuse is extremely specific, but not particularly sensitive. Efforts are needed to improve police evaluations. The effect of increased legal actions on recurrent alcohol and drug-related injuries remains to be seen.