Supplementary reports were made for the 850 single-vehicle accidents on route 66 from june through october 1964, by the highway patrols of seven states. Of these accidents, 2.0 percent were fatal and 86.5 percent involved passenger cars; 92 percent of the vehicles first ran off the pavement, 4.5 percent first hit an object while still on the pavement, and the remaining 3.5 percent first turned over on the pavement. Twenty-nine tables of factual data were abstracted. One vehicle in five had a trailer, one passenger car in seven. Of all vehicle occupants 23.0 percent had seat belts available, but of these only 48.3 percent were using them. Distribution of drivers by age and sex differed little from accidents in general, but distribution by hour of day did not show usual morning and evening peaks. With a risk index for standard cars established as 1.00, that for compact cars was 2.23, and for small and sport cars 3.49. Adding a trailer multiplied the risk index by four for all three types of cars. Twenty-one tables of opinions of investigators relating to possible causal factors were abstracted. These indicated that 15.5 percent of the drivers were believed to be exceeding the speed limit at the time of the accident. Speed limits varied from 30 to 75 mph, with most of the route at 70. The most prominent factors were as follows: for the road, slippery surface, 13.0 percent; for the driver, sleep, 24.8 percent, distractions, 8.7 percent and trailer hitch failure 2.5 percent. Consideration was given in the final section to the reilability of the opinions expressed by investigators. Except for those relating to speed, opinions seemed to derive largely from driver statements. /author/.
Abstract