Introduction of 30 km/h as general speed limit in European cities - what effects can be documented?

We have assessed and organized information related to the introduction of 30 km/h general speed limits in six European cities, as well as Spain. The decision to introduce such a speed limit can be taken at different levels – by national authorities defining speed limits in all cities, political authorities in urban municipalities, or authorities at different levels on parts of the road network they administer. With some exceptions for main roads, the cities have implemented the 30 km/h general speed limit on all or most streets and roads throughout the city or city region. Information about speed limits and enforcement of compliance are important elements of implementation. The cities have documented that the measure has produced desired effects, such as lower speeds, high levels of compliance, reduced noise and local pollution, no increase in travel time or congestion for vehicular traffic, and significantly fewer accidents, especially serious ones and those involving pedestrians and cyclists.