To make a detailed examination of the relation between the interval in approaching traffic which a driver judges to be safe for overtaking and his actual performance in overtaking a controlled experiment was carried out on an airfield and the result compared with those of a short series of observations on a two-lane section of a trunk-road. It was found that the values obtained from the measurements, on the airfield, of judgment and performanoe of a small sample of young, fairly skilled, male drivers are consistent with the observation. made of the vehicles on a trunk road in August. It is concluded that drivers should not attempt a manoeuvre about which they have any doubts, not only because they have a smaller safety margin for their action, but also because they take longer to decide to act. Drivers should be aware of the limitations of their vehicles, particularly at high speeds (over 40 mile/h) when judgments are found to be less realistic than at lower speeds and opportunity to gain experience is limited. (Author/publisher)
Abstract