The effects of different breath alcohol concentration and post alcohol upon driver’s driving performance

A simulator study was conducted to investigate the effects of (1) different breath alcohol concentration (BrAC) consumption (0 mg/l vs. 0.25 mg/l vs. 0.40 mg/l vs. 0.50 mg/l) and (2) after drinking alcohol with ~BrAC = 0 mg/l upon driver driving behavior and subsidiary task performance. Two load road environments were developed, low vs. high, and each required approximately 20 minutes of driving. In addition to driving safely, participants were instructed to perform the CFF (critical flicker fusion) value and write NASA-TLX questionnaire. Eight participants (6 males; 2 females) with normal driver´s license participated in this 2 x 4 within-subject experiment. Results showed that (1) the mental workloads after the drunk driving section is the largest, (2) the longer the drivers were on the road, the wearier the drivers felt, (3) high BrAC level (.5 mg/l) caused bad driving performance, and (4) complex road situations also increased the risk to driving safety. However, no significant difference between drunk driving and post-alcohol driving was found and that indicated that not only drunk driving affects traffic safety, post-alcohol impairment also affects traffic safety seriously.