News article

Updated estimates of the relationship between speed and road safety at the aggregate and individual levels

SWOV researcher van Schagen coauthored the article 'Updated estimates of the relationship between speed and road safety at the aggregate and individual levels'. The relationship between the speed of traffic and road safety has been the subject of extensive research. It is widely accepted that speed limits and their enforcement are effective road safety measures. Nevertheless, raising speed limits is often a popular measure.

One may ask: Is speed still as important for road safety as it was in the past? Can new vehicle safety systems have made speed less important? Modern cars are better equipped both to avoid accidents and make them less serious (by protecting occupants better) than cars were 15–20 years ago. On the other hand, their speed performance has increased.

The first objective of this paper is to review evidence concerning the relationship between the speed of traffic and road safety based on studies published after 2000 and in which parts or all of the data refer to the period after 2000. The main question is whether the relationship between speed and road safety remains as strong as previous studies have indicated. The second objective is to assess whether the relationship between speed and accident involvement at the individual level, i.e. the relationship between a driver’s speed and his or her accident involvement rate, has the same shape and strength as the aggregate relationship between the mean speed of traffic and the number of accidents or accident victims.

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