@phdthesis{Schnabel2011,
  author    = {Schnabel, Eva},
  title     = {Alcohol and driving-related performance - A comprehensive meta-analysis focusing the significance of the non-significant},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69959},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {The present work reviews the experimental literature on the acute effects of alcohol on human behaviour related to driving performance. A meta-analysis was conducted which includes studies published between 1954 and 2007 in order to provide a comprehensive knowledge of the substance alcohol. 450 studies reporting 5,300 findings were selected from over 12,000 references after applying certain in- and exclusion criteria. Thus, the present meta-analysis comprises far more studies than reviews on alcohol up to now. In the selected studies, different performance tests were conducted which were relevant for driving. The classification system used in this work assigns these tests to eight categories. The main categories consist of several sub categories classifying the tasks more precisely. The main categories were: (1) visual functions, (2) attention (including vigilance), (3) divided attention, (4) en-/decoding (including information processing and memory), (5) reaction time (including simple reaction time and choice reaction time), (6) psychomotor skills, (7) tracking and (8) driving. In addition to the performance aspect, the classification system takes into account mood and social behaviour variables related to driving safety like tiredness or aggression. Following the evaluation method of vote-counting, the number of significant findings and the number of non-significant findings were summarised per blood alcohol concentration (BAC) group. Thereby, a quantitative estimation of the effects of alcohol depending on the BAC was established, the so-called impairment function, which shows the percentage of significantly impaired findings. In order to provide a general overview of alcohol effects on driving-related performance, a global impairment function was established by aggregating all performance findings. The function is nearly linear with about 30\% significant findings at a BAC of 0.05\% and 50\% significant findings at a BAC of 0.08\%. In addition, more specific impairment functions considering only the findings of the single behavioural categories were calculated. The results revealed that impairment depends not only on the BAC, but also clearly differs between most of the performance categories. Tracking and driving performance were most affected by alcohol with impairment beginning at very low BACs of 0.02\%. Also psychomotor skills were considerably affected by rather low BACs. Impairment of visual functions and information processing occurred at BACs of 0.04\% and increased substantially with higher BACs. Impairment in memory tests could be found with very low BACs of 0.02\%, but varied depending on the kind of memory. Performance decrements in divided attention tests could also be found with very low BACs in some studies. Attention started to be impaired at 0.04\% BAC, but - as in vigilance tasks - considerable impairment only occurred at higher BACs. Choice reaction time was affected at lower BACs than simple reaction time, which was - together with the critical flicker fusion frequency - the least sensitive parameter to the effects of alcohol. To conclude, most skills which are relevant for the safe operation of a vehicle are clearly impaired by BACs of 0.05\%, with motor functions being more affected than cognitive functions and complex tasks more than simple tasks. Generally, the results provided no evidence of a threshold effect for alcohol. There was no driving-related performance category for which a sudden transition from unimpaired to impaired occurred at a particular BAC level. In addition, a comparison was made between the present meta-analysis and two reviews of Moskowitz (Moskowitz \& Fiorentino, 2000; Moskowitz \& Robinson, 1988). Moskowitz reported much lower BACs at which performance was impaired. The reasons for this discrepancy lies in a different way to review scientific findings. On the one hand, Moskowitz focused on significant findings when selecting studies and findings for his reviews. On the other hand, the evaluation method used by Moskowitz ignored non-significant findings and counted each study once at the lowest BAC for which impairment was found. Those non-significant findings are as important as the significant ones in order to determine thresholds of impairment. Therefore, in contrast to Moskowitz, the present work describes the effects of alcohol with functions considering also the non-significant findings. The significance of the non-significant is emphasized with respect to the selection procedure as well as to the evaluation method.},
  subject      = {Trunkenheit im Verkehr},
  language  = {en}
}