EFFECTS ON DRIVING ABILITY
Walsh et al. (2004) point to Berghaus and Grass (1997), who summarized more than 500 experimental studies in which the effects of benzodiazepines on driving-related performance were assessed. Benzodiazepines are central nervous system depressants used therapeutically to produce sedation, induce sleep, relieve anxiety and muscle spasms, and to prevent seizures ( Jones, Shinar, and Walsh, 2003). The correlation between serum benzodiazepine concentrations and performance deficit for most of the benzodiazepines investigated was almost linear. On-road driving tests using different benzodiazepines and zopiclone31 demonstrated adverse effects on the standard deviation of lateral position (a measure of lane keeping). Subjects tested the morning after using benzodiazepines as hypnotics showed impairment comparable to a BAC of .05 to .10 (O’Hanlon, et al., 1986). Walsh et al. (2004) state that based on the present knowledge, benzodiazepines constitute a considerable risk to traffic safety, both in therapeutic doses and to a much higher degree at higher doses.
31 Zopiclone (brand name: Imovane) belongs to the group of medicines called central nervous system (CNS) depressants (medicines that make you drowsy or less alert). This medicine is used to treat insomnia (trouble in sleeping).