O'Hanlon J F, Haak T W, Blaauw G J, Riemersma J B
Science. 1982 Jul 2;217(4554):79-81. doi: 10.1126/science.7089544.
Nine expert drivers operated an instrumented vehicle in tests over a highway at night after being treated with diazepam (5 and 10 milligrams), a placebo, and nothing. They reacted to 10 milligrams of diazepam with increased lateral position variability. Potentially dangerous impairment was inferred from the reactions of some subjects.