An empirical study of the performance efficiency of subjects engaged in highway navigation tasks is described. The study was designed to assist in quantifying the amount of excess travel that is due to navigational failures and to assess the relative contributions of trip-planning and route-following errors. Demographically representative samples of drivers were observed driving and navigating seven-stop automobile tours in Connecticut and Wisconsin, during both day and night, under three levels of trip planning. The distances driven and the times used were compared with those necessary to accomplish the same tour using optimum routes. Analysis of the data obtained indicated that a significant proportion of the total vehicle miles traveled, and a larger proportion of the total time spent driving, may represent navigational waste. Driver demographic attributes, and time of day, had little effect on driver performance. No significant differences due to the subjects' trip-planning efforts were noted.(A).
Abstract