A low cost, fixed-base driving simulator was used to investigate the impact of a new car cellular audio phone system on driver behaviour. Twelve subjects drove a 30-min simulated driving scenario with a low driving load and another twelve subjects drove a 30-min scenario with a high driving load. Participants were instructed to follow traffic and speed rules, and while driving, participants also had to conduct telephone communications of different lengths and complexities as well as perform a detection task. Results showed that in the low driving load environment, and when telephone communications were short, reaction time and accuracy for the detection task and several objective measures of driving performance (i.e. mean lane position, and variances in lane position, lateral acceleration and steering wheel angle) were all relatively good. However, these good performance results were evidently achieved because the short conversations increased the workload and thus the arousal level; when arousal levels were already high (i.e. in the high driving load condition), the short conversations were associated with a degradation in performance measures, presumably because attentional resources of the subjects' become over-stretched and thus the subjects adopt a different attention allocation strategy. (Author/publisher)
Abstract