A programme of research has been carried out examining psychological factors which influence an individual's risk of a road traffic accident. Data were collected in a series of postal surveys, by observations of driving behaviour, and by using a computerised simulation of some components of the driving task. In the surveys, drivers were followed up for a period of three years to examine the degree of consistency in their driving behaviour and accident rates over time. The postal surveys asked about driving behaviour, accident history, age, sex, annual mileage, personality and the way that respondents generally made decisions. Drivers who reported that they frequently drove fast or exceeded urban and motorway speed urban and motorway speed limits had more accidents. This relationship was in addition to known effects of age, gender and annual mileage on accident risk. Faster driving speed was more closely associated with speed-related accidents than any other accident type, strongly suggesting a direct causal role between faster driving and accident risk. Self-reported driving speed was found to be consistent over the three years it was recorded. Men were found to drive faster than women and there was a negative association between age and fast driving. Driver's self-reported speed was shown to provide a good indication of actual driving speed as observed by passengers and to correlate with speed adopted in a computerised driving simulator. Respondents who generally made decisions without carefully examining the options were at greater risk of a road accident. Likewise respondents who generally gave little consideration to social values or the needs of others were at greater risk of an accident. There was no evidence of a relationship between skill at a computerised driving task and accident risk. The surveys found that drivers were quite consistent in their risk of having a road accident over the three years that they were followed up. Having had an accident in a one-year period was associated with a doubling of the odds of having an accident in the following two years. Drivers who had an accident in which their own behaviour played some role had four times the odds of having a similiar accident in the next two years than did accident free drivers. Drivers who had a speed related accident in one year had their odds of having a similar accident in the next two years raised ninefold. Respondents were found to be able to report relatively accurately their annual mileage broken down according to whether or not they carried passengers, where driving in the course of work, and were driving company cars. However they did not appear to be able to provide accurate reports of mileage on different types of road nor of mileage in the dark versus during daylight. There was evidence that driving a company car carried a higher risk of accident than driving a private car and driving in the course of work carried a slightly higher risk than commuting or driving for other purposes. The relationship between speed choice and accident risk and also the relationship between accident risk and personality and general decision making habits both have implications for road safety interventions and these are discussed. (A)
Samenvatting