Lower speed limits also yielded environmental benefits, with emissions decreasing on average by 18%, noise pollution levels by 2.5 dB, and fuel consumption by 7%, indicating enhanced fuel efficiency and reduced environmental impact.
In this study they did not look into the reduction of particulate matter from tire and brake abrasion, which is a major source of pollution caused by cars, so the environmental benefit is even greater than they found.
Review of City-Wide 30 km/h Speed Limit Benefits in Europe
In this study they did not look into the reduction of particulate matter from tire and brake abrasion, which is a major source of pollution caused by cars, so the environmental benefit is even greater than they found.