Federal Highway Research Institute


This website uses cookies. These are used for intermediate storage during ordering or registration processes. Data such as frequency of use or behaviour are not recorded. Here you can find out more about data protection and possibilities for contradiction.


Route-specific accident analyses on motorways

In its function as an accident research centre, the Federal Highway Research Institute has performed accident analyses of motorways for many years. Official accident statistics are used for this purpose. The aim is to identify motorway sections with especially high accident rates.

Absolute accident figures are not very useful in comparing accident patterns. Considered instead are annual accident rates per route kilometre or annual mileage per route (accidents per vehicle per kilometre). For a summary evaluation of accidents of different severities, for instance those involving personal injury and damage to assets, accident figures are often considered in terms of costs.

The picture shows a map Safety Potential TEN-T (Roads) Sections with safety potential TEN-T (Roads)

Safety potential is the most important characteristic accident parameter for road building authorities. Their objective is to identify network sections on which safety improvement measures are expected to have the greatest effect.

Safety potential describes the extent to which accident costs on a road section exceed the value expected if the section met all relevant safety standards given the same traffic volume.

This potential can be utilized partly through appropriate structural or traffic-related safety improvement measures by the authorities; however, detailed accident analyses are still needed here.

Network-wide determination of safety potentials according to the recommendations for safety analysis of road networks by the research society for roads and transport permits road authorities to identify sections which require further detailed investigations and which can be expected to undergo the most durable improvements.

The picture shows a map Major accident clusters on motorways 2016 Major accident clusters on motorways 2016

A conventional approach also serving the road building authorities' purposes is the determination of accident clusters. An accident cluster exists when the number of accidents surveyed on a section is significantly higher than the accident rate expected considering the traffic volume and section length.

In contrast to safety potential, a determination of accident clusters does not consider different accident severities. This characteristic variable only represents accidents involving injury to persons.

The maps and accident risk parameters published on this website result from research projects regarding "Section Related Accident Analyses on Federal Motorways".

The accident risk parameters which are the basis of these maps will be provided upon request.

Further information


The Excel files for the whole Federal Motorway network will be provided upon request. E-mail: unfallkenngroessen(at)bast.de