Evaluation results from 40 different cities across Europe:
A systematic review by George Yannis and Eva Michelaraki collected data from 40 European cities - including Brussels, Paris, London, Helsinki and Zurich - and found that the implementation of 30 km/h speed limits have led - on average - to:
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up to 37% reduction in road crashes, fatalities, and injuries
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emissions decreased on average by 18%
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noise pollution levels decreased by 2.5 dB
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fuel consumption decreased by 7%, indicating enhanced fuel efficiency and reduced environmental impact.
Some study findings with regard to improved air quality:
- In Edinburgh, UK, the speed limit on nearly all of its roads was reduced from 30 mph to 20 mph. One year later, the areas with the reduced speed limit experienced a reduction in particulate matter (PM) by 8%.
- A similar pattern was identified in London, where an 8–10% decrease in PM was observed, after the introduction of 20 mph zones.
- In January 2017, Berlin, Germany, implemented 30 km/h speed limit to five main roads. Following this measure, improvements in air quality were observed. In particular, nitrogen dioxide and monoxide emissions decreased by up to 29% from 2017 to 2020 in four out of the five cases. [ here you can read more about Berlin’s Clean Air Plan ]
- Furthermore, in June 2018, Bilbao, Spain, reduced the speed limit to 30 km/h with the aim of reducing noise and air pollution. One year later, the city experienced reductions in air pollution; an 11.4% decrease in NO2-μm3, a 17.1% decrease in NOX-μm3 and a 19.1% decrease in PM10 was identified.
- Another important finding of the impact assessment in the city of Graz, Austria, was that noise levels and NOx emissions dropped by 2.5 dB and 25%, respectively, when maximum speeds of 30 km/h were introduced.
In conclusion: The 30 km/h limit saves lives and improves the quality of cities!
