Diss. (sammanfattning) Uppsala : Univ., 2001

The thesis deals with hangover effects of alcohol and carry-over effects of benzodiazepine hypnotics on car driving performance. One study is presented regarding effects of alcohol, and two studies regarding effects of hypnotics. A driving simulator was used in all three studies. Real car driving was used in one of the studies. A validation study is also presented. Comparisons were made between driving behaviour - speed and lateral position - in a real and a simulated road tunnel. Absolute validity was not quite satisfactory, whereas relative validity was satisfactory for both measures. It was concluded that results obtained in the driving simulator may well be generalisable to similar test situations in real car driving. In the alcohol study, testing was performed in simulated driving in a sophisticated driving simulator during the acute intoxication phase and four times during the following day. Performance in a fast driving task was severely impaired in the acute phase, and slightly impaired the following day. For the two studies on hypnotics, the first study compared carry-over effects of nitrazepam 5 mg, which is a drug with a long elimination half-life, with triazolam 0.25 mg, which has a very short elimination half-life. Effects were found after a single dose of nitrazepam taken at bedtime in monotonous simulated driving, but not on performance in an emergency situation during real car driving. No effects appeared for triazolam. After three consecutive nights of medication, no effects were any longer apparent. In the second study, where only a simulated monotonous driving task was used, acute effects were found for nitrazepam 5 mg and for brotizolam 0.25 mg, whereas no carry-over effects appeared after medication for three consecutive nights.