Driver Judgments in Passing on the Highway

The passing of vehicles on a two-lane highway presents a fundamental hazard and yet is necessary for the efficient operation of traffic on such roads. A study of the engineering or physical factors and ot the human factor requirements for such overtaking and passing has been undertaken in order to obtain data applicable to the sight-distances sufficient for passing. Although many estimates of the distance requiremenets have been made, practically all of these have been bases on certain assumptions as to driver behavior and vehicle performance. We felt that the only valid appriach was to obtain the actual performance of the everyday driver and everday car on th ehighway. Two major findings on the human factor in this study will be reported in this paper, and the physical aspects will be reported elsewhere.