Off-the-road accidents - who are the drivers and why do these accidents occur?

This paper documents a study of off-the-road accidents conducted by SINTEF Transport Research, on commission from the Norwegian Public Roads Administration. The aim of this study has been to present knowledge about drivers who run off the road and identify circumstances of these accidents. This information provides a base to find more efficient measures to reduce the number of single accidents. The study has been conducted with a broad methodological approach: Statistical analyses, review of research literature, surveys and telephone interviews, and an in-depth study of police documents from a selection of off-the-road accidents. The main results show that there are different contributing factors to single accidents depending on the age of the drivers. The youngest drivers, especially men aged 18-19 years, are highly overrepresented in the off-the-road accident statistics. Many drivers in the youngest age group take great risks in traffic, and suffer from poor driving experience, often leading to poor handling of difficult driving conditions. Elderly drivers more often suffer from capacity problems and attention problems. Also, falling asleep, health conditions, and difficult driving conditions may have resulted in such accidents in this age group. For single accidents involving elderly drivers, there is very little evidence of speeding, alcohol or drugs. For male drivers aged 20-29 years, the combination of speeding and influence of alcohol and/ or drugs is a very important cause of off-the-road accidents. In these accidents there seem to be two categories of drivers: - Persons who do not intend to drive carelessly, but, as an isolated incident, the influence of alcohol led to bad judgment and impaired driving; - Persons for whom partying, alcohol, drugs, risky behaviour and crime, is their lifestyle. Many off-the-road accidents happen during the weekends and leisure time, and at night. This may be due both to a higher frequency of so-called party driving, and to reduced traffic, so that when accidents occur, they are more likely to be single accidents than collisions. Following the same reasoning, the increased usage of rails separating opposite lanes may lead to an increased number of off-the-road accidents in comparison to head-on accidents in the future. The study concludes by proposing measures to reduce the number of off-the-road accidents for different age groups. Several advanced driver assistant systems are promising, but need adaptation to individual and societal demands. Information contents and channels need to be more adapted to each age group. However, many off-the-road accidents happen as a consequence of a broader societal problem, which need to be addressed on a preventative level.