Samenvatting
An experiment is described to investigate the effects of 3 levels of marihuana and 2 levels of alcohol, both alone and in combination, on driver behaviour. Twelve subjects were tested in a driving simulator using a double-blind, full placebo, counterbalanced design. The only marihuana impairment observed, other than speed reduction, was during the divided attention tracking task. During this task effects were observed on both speed variability and uncorrelated steering activity.