Effect of alcohol on failures. A . Failure rate per alcoholic condition for each step cycle phase separately, and in total. LSt = Late Stance, ESw = Early Swing, MSw = Mid Swing. A0: placebo, A1: first alcohol, A2: second alcohol. (**p < 0.01, compared to A0). B. Model of the probability of failing to avoid the obstacle with increasing blood alcohol concentrations for the most time critical situations.