The first ever scientific review of city-wide 30 km/h speed limit benefits in Europe can be found here.
A literature review of the effectiveness of 30 km/h speed limit can be found here.
A Cost-Benefit Analysis of reducing speed limits to 30 km/h in Athens can be found here.
Safety
37%
reduction in fatalities
City-wide 30 km/h speed limit can improve road safety by decreasing travelling speed and reducing the risk of crashes occurring and the severity of crashes that do occur. Findings from several cities implemented 30 km/h speed limit demonstrated an average of 23%, 37% and 38% decrease in road crashes, serious injuries and fatalities, respectively. For instance, a 46% reduction in road crashes and a 55% reduction in fatalities was observed in London and Brussels.
Environment
18%
reduction in emissions
City-wide 30 km/h speed limit can reduce car dependency and harmful vehicle emissions that contribute to climate change. The implementation of lower speed limits in several cities resulted in significant environmental benefits, including an average 18% reduction in emissions and an average 2.5 dB reduction in noise pollution. For example, a 29% and 25% decrease in CO2, NOx and PM emissions was found in Berlin and Graz, while noise pollution dropped by 3 db in Paris.
Energy
7%
reduction in fuel consumption
Lower speeds can lead to lower fuel consumption, while smoother traffic flow can lead to additional fuel economy. After the introduction of 30 km/h speed limit in cities, it was found that fuel consumption decreased by an average of 7%. In particular, a 12% and 10% reduction in fuel consumption was demonstrated in Münster and Brussels, respectively.
Traffic
2%
reduction in traffic congestion
Reducing speed limits can have an impact on traffic volumes. Results from several cities implemented 30km/h indicated that the reduction of city-wide speed limit contributed to an average 2% decrease of traffic congestion. It was also demonstrated that 30km/h speed limits improved traffic flow and travel times as there were less stop/start traffic movements. More specifically, traffic congestion decreased by 9% and 2% in Grenoble and Bilbao, respectively.
Liveability
50%
increase in pedestrians and cyclists
City-wide 30 km/h speed limit can create progressively a friendly environment for pedestrians and cyclists, making it safer and more enjoyable for them to travel on foot or by bike but also on public transport. Lower speeds reduce reliance on individual vehicles and leads to gradual modal shift from passenger cars to public transport and shared and active travelling, which in turn creates new opportunities for redistribution of public space towards a higher quality of life in cities. Interestingly, a 55% increase in the number of cyclists was observed in Lille.
Health
improved public health
Reduced speed limits can lead to increased physical activity levels among travellers, which has numerous health benefits. Regular physical activity has been associated with reduced risk of chronic diseases, improved mental well-being and enhanced overall quality of life. Not forgetting that calm driving in lower speeds is a means of promoting healthier living also for drivers. With the introduction of 30 km/h speed limits in several European cities, findings revealed that there were less stressed citizens, with fewer health problems, and, therefore, a quieter city was promoted.
