Single-car road deaths--disguised suicides?

If a substantial proportion of these deaths are deliberate (1) their seasonal variation and their age distribution would be similar to those of suicides; (2) they would occur independently of road conditionis, while other single-car fatalities would be more likely to occur when road conditions are adverse. Information about single-car accidents for the two years 1969 and 1970 was obtained from the Transport and Road Research Laboratory, which provided details of the age and sex of the driver, the number of occupants, the road conditions, and the month of occurrence. The seasonal variation and age distributions of the road deaths and of suicides were compared, as were the incidences of single-car, single-occupant deaths and single-car, multipleoccupant deaths occurring in different road conditions. A total of 528 single-car, single-occupant road deaths occurred in Great Britain in 1969 and 1970 (table). Both single-car, single-occupant deaths and suicides had a significant seasonal variation, but while the peak for suicide was in April that for the road deaths was in November. When the suicide distribution and that of road deaths were compared they differed significantly (X2-58-32; df= 11; p <0 001). The age distribution of single-car road deaths when the driver was alone and when passengers were present did not differ and were highest in the young age groups (15-24 and 25-34). In contrast, suicides increased with age. The age distributions of single-car, singleoccupant road deaths and suicides differ significantly (Z2=693-98; df=4; p<0-001). Similar proportions of both categories of road deaths occurred when road conditions were dry, wet, or snowor ice-covered. The distributions did not differ significantly (z2= 1-89; df= 2; p= 0-39). Adverse road conditions therefore affected both types of accident to a similar extent.