Report: Positive experiences with 30 km/h speed limit in European cities
A speed limit of 30 km/h contributes to more sustainable urban development, concludes a report that examined experiences from a number of European cities.
"Speeds decreased and the number of traffic accidents was significantly reduced in all the cities we found data for," says Aud Tennøy. She is the chief researcher on urban development and urban transport at the Institute of Transport Economics (TØI).
In addition to fewer accidents, the researchers found that lower speeds helped reduce noise and noise disturbances. People felt it was more pleasant and safer to walk and cycle.
Discussing more use of 30 zones in Norway
The study will be used as a basis for discussions about increasing the use of 30 zones in Norwegian cities. It looked at European cities that have introduced 30 km/h (20 mph) zones in large zones, entire cities, or as a general speed limit without implementing physical speed-reducing measures.
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Surveys in several cities showed that most residents were positive about lowering the speed limit, and even more were convinced after the measure was implemented. Few people wanted to raise the speed limit again.
"The results are consistent across the cities and towns we have data from. We believe the measure is likely to have positive effects that support more sustainable urban development in other cities that adopt it, including in Norway," says Tennøy.
Experts are divided
The Norwegian Public Roads Administration is now reviewing the criteria for speed limits and how they are applied. There is disagreement and uncertainty among Norwegian experts about the pros and cons of using the 30 km/h speed limit more widely.
Some concerns are that buses and, to a lesser extent, cars might take longer to reach their destinations. There is also doubt about whether drivers will adhere to the speed limit, whether the measure will have the desired effect, and whether the proposal is in line with regulations, according to TØI.
Travel time for public transport increased a little, but the effects were minor, according to the report.
Will Norwegians respect a lower speed limit?
One objection in the Norwegian debate is that the 30 km/h limit will not be respected, and that could lead to less respect for traffic rules in general, which might cause more accidents.
"If this were true, we should have seen more traffic accidents in the cities we studied, but we actually found the opposite. We also saw that the effect spread – speeds and accident numbers went down even in streets and areas where the speed limit hadn't been changed," says Tennøy.
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Read the Norwegian version of this article on forskning.no
Reference:
Tennøy, A. & Pettersen, G.R. Introduction of speed limit 30 km/h in
large zones and entire cities to achieve the
goal of sustainable urban development. Processes, discussions, implementation and effects, Institute of Transport Economics Report, 2025.
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