Speed effects of automatic enforcement on urban streets

A recent study evaluated the effects on driving speed of automatic speed enforcement on the street network in Helsinki.  Installing automatic enforcement reduced speeding and in particular the proportion of excessive speeding. There was also a reduction in the proportion of speeding overall and mean speed.

Reducing driving speeds has been identified as the one of the main measures for improving traffic safety in urban areas. In 2018, the city of Helsinki updated their speed limit principles and introduced speed limit changes on the street network. It was also decided to install 70 new automatic enforcement sites during the years 2020–2024. In February 2021, the first new automatic speed enforcement sites were built.

This study compared driving speeds before (September-November 2019) and after (October-November 2022) the installation of the automatic enforcement sites. The study design was a before-after study with control sites. The study analysed point speed data at eight locations, based on field measurements and the city’s automatic measurement points.

Significant reduction in driving speeds

The proportion of freely driving vehicles exceeding the speed limit by more than 10 km/h dropped by 56% (12% -> 5%) after the introduction of automatic enforcement. The corresponding reduction for speeding overall was 16% (49% -> 41%). There was also a reduction in mean speed of all vehicles was after the introduction of automatic enforcement. In speed limit zones of 40 km/h, the average speed dropped by 2.1 km/h and in speed limit zones of 50 km/h it dropped by 1.1 km/h. The results were in line with previous studies, although the changes in driving speed were smaller.

Overview of automatic enforcement in Finland

In Finland, the road authority is responsible for the automatic enforcement site, and the police for the enforcement. The police rotate their cameras i.e. an automatic enforcement site is not always equipped with a camera. At the automatic enforcement site, a picture is taken when the preset threshold is exceeded. Exceeding the speed limit by 3–6 km/h results in a warning, by 7–20 km/h in a traffic penalty fee and by more than 20 km/h in an income based daily fine.

For more information:

Fanny Malin

VTT Technical Research Centre of Finland


Link to full report (in Finnish): https://julkaisut.hel.fi/fi/julkaisut/automaattisen-liikennevalvonnan-nopeusvaikutukset-helsingin-katuverkolla 

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