It is pointed out that when the risks attending night driving are increased by poor illumination the detection and elimination of the accident-prone must be even more desirable than under normal conditions. "The available evidence tends to show that accident proneness is a measurable quality, manifesting itself among motor-drivers no less than among industrial workers."
Summarizing their conclusions, the authors state: "It is clear from the data that accident proneness among motor-drivers is an important factor in the causation of accidents." Those who failed in certain psychological tests had a higher average accident rate than those who passed, and those who had an undue number of accidents in their initial period of exposure tended to have a higher subsequent accident rate than others.
Accident proneness manifested its: If in all kinds of accident and throughout all conditions of exposure. "It was shown that experience, although it lessens the accident rate, does not affect differences between those who are specially prone and others. The former always have a higher accident rate than the latter, in spite of the increasing experience of both."
Discussing the difficulty of providing a suitable intelligence test for adults who left school at fourteen, the authors state: "The men feel a strange nervousness when faced with a pencil and a set of printed questions, and the general trend of their remarks is to the effect that they have left school a long time and cannot be expected to do tests of this kind."
Evidence of the unsuitability of the group intelligence test for such subjects was provided by the fact that the drivers in one group had an average score in the test of 64, while a group of apprentices of mean age sixteen scored an average mark of 120, This could not be taken to indicate that the drivers were really greatly inferior in intelligence to the apprentices, but rather that the test was not suitable for both groups, In the hope that it might be less alarming, a simpler test was devised, "But," it is stated, "we do not feel that we have succeeded." The men still appeared unduly nervous.
Text read from the printed page and cleaned; old type leaves the occasional error.