Restricting a city’s speed limits to 20mph reduced road deaths by nearly a quarter and serious injuries by a third, research revealed. A study found accident rates across Edinburgh fell even without extra traffic-calming measures and police patrols – making the scheme cost-effective.
Prior to the new restrictions, 45 out of 100 cars in Edinburgh travelled above 25 mph – but one year later, the figure had dropped to 31. Average speeds on affected roads also fell, according to the study – the UK’s most extensive evaluation of 20mph speed limits so far.
Researchers said the number of collisions in one year fell by 40 per cent to 367, and there were 409 fewer casualties – a drop of 39 per cent. A breakdown of the casualty figures reveals that fatalities dropped by 23 per cent and serious injuries fell by 33 per cent.
Experts said the ‘relatively modest’ cost of replacing speed limit signs not only improved road safety but also enhanced quality of life for residents. Researchers worked with traffic authorities to gauge the effectiveness of 20mph restrictions introduced by the City of Edinburgh Council in 2016.
The new limits applied in 80 per cent of Edinburgh’s streets in a bid to cut accidents, encourage more walking and cycling and create more pleasant neighbourhoods. The research, which also assessed a smaller scheme in Belfast, found that reducing traffic speed also helps to create better quality environments.
Researchers measured liveability – safety, health, sustainability, education, transport, amenities and living standards – and found it improved in both cities after the introduction of speed restrictions. One year after implementation, the number of people who were supportive of the speed limits increased, as did their willingness to obey the limits.
Project leader Professor Ruth Jepson, of the University of Edinburgh, said: “The study shows that city-wide speed reductions can reduce collisions and casualties and that they were increasingly accepted by the local community.”
The City of Edinburgh Council’s former transport and environment convener, Lesley Hinds – who proposed the scheme – said: “It is encouraging to see the reduction in deaths, accidents and speeds. It is also good there is an increase in support from the public in residential streets as well as in the city centre.”
The Belfast scheme, which was restricted to city centre streets, led to a two per cent drop in casualties and collisions, and minor reductions. Researchers say results reflect the scheme’s narrower reach and its implementation in an area where traffic speeds were already low prior to the trial – on average less than 20mph.
Professor Ruth Hunter, of Queen’s University Belfast, said: “City-wide expansion of 20mph limits in Belfast would likely lead to further reductions in casualties, collisions and other important public health outcomes.”
