ABSTRACT
This chapter provides an update of a review article published in Forensic Science Review in 2015 covering results from epidemiological studies on the association between use of non-alcohol drugs and road traffic crashes (RTC) involvement for the period 1998–2015. Experimental studies can be used to determine whether a drug may impair driving-related functions and are most commonly performed for medicinal drugs using healthy individuals taking relatively small drug doses. The use of drugs by drivers who are involved in RTCs is investigated in descriptive cross-sectional studies. Case-control studies are in general used to study the association between a defined exposure and an outcome of active exposure and are sometimes regarded as optimal methodological approach for studying RTC risk when driving after using alcohol or drugs. Case-crossover studies are comparing the number of RTCs for each individual during periods of drug use with periods without drug use. Each person in the study is both a case and his own self-matched control.
