This is not an unusual scenario. Around 43,000 accidents involving injuries and fatalities and caused by a failure to drive at a safe distance were recorded in Germany’s federal statistics in 2008. They make up around 13 percent of all accidents in this category. On freeways 29 percent of all accidents involving fatalities were caused by rear-end collisions. A glance at the insurers’ accident database also shows that serious and fatal injuries are more likely in accidents between two moving vehicles (as in the UDV’s crash test) than in accidents in which one vehicle is stationary. The severity of the accident increases again if more than two vehicles are involved in the crash. A serious injury or fatality can be expected in one in three such accidents.

A closer analysis of these rear-end collisions outside built-up areas reveals that 80 percent of the drivers who cause them are male and that 8 out of 10 of these accidents occur on the open road – and thus without any intersections, junctions or roundabouts to disturb the flow of traffic.

So why do so many drivers not keep a safe distance although there is a relatively simple rule to keep to? (Namely, divide your speed in km/h by half to calculate how many meters you should be behind the car in front.) The answer is that there is a fatal combination of psychological factors at play. Drivers generally estimate they are driving more slowly than they actually are and that they are further behind the car in front than they actually are. In addition, the typical driver causing one of these accidents (a male, middle-aged, frequent driver with a good job, many years of driving experience and a powerful car) believes that he can compensate for the increased risk with his driving experience.

In the view of the UDV, the following measures could alleviate the problem:

• Intelligent cruise control systems in conjunction with emergency braking systems should be mandatory in all cars.
• More retrofittable distance warning systems should be available and their installation recommended.
• People should be given better information about the inaccurate estimates they make and the aids they can use (the speedometer and the marker posts at the side of the road).
• Regular checks should be carried out, and sanctions should be imposed on the most incorrigible offenders.

The crash tests can be seen at www.youtube.com/unfallforschung.