20mph zones reduce cycling casualties by almost a fifth, say researchers

The introduction of 20mph zones in parts of London has led to a reduction of almost a fifth in the number of accidents involving cyclists in London, according to research published in medical journal, the BMJ.

The study found that introducing 20mph zones led to a 41.9% fall in the number of road casualties, with the biggest impact seen in accidents involving younger children, as well as in accidents involving fatalities or serious injuries.

The number of cyclists killed or seriously injured in road traffic accidents fell by 17% in 20mph zones, with a greater drop observed in accidents involving children.

Researchers added that they found no evidence of casualties having migrated to roads adjacent to 20mph zones that had higher speed limits – indeed these saw an average 8% reduction in casualty numbers.

The study, undertaken by a team led by Dr Chris Grundy from the Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, was conducted by analysing geographically coded police data regarding road casualties from 1986 to 2006.

It concluded: “This evidence supports the rationale for 20mph zones not just in major cities in Britain but also in similar metropolitan areas elsewhere. Indeed, even within London, there is a case for extending the currently limited provision of such zones to other high casualty roads.”

Transport Secretary Lord Adonis has also given his backing to the introduction of 20mph zones. Named personality of the month for December on the Cycling England website, in response to the question, “What most encourages you about cycling where you live?” he replied,
”new 20 mph zones throughout Islington’s residential streets, which together with traffic calming is making the area safer for cyclists.”

No doubt the minister will have welcomed the news earlier this month that the London Borough of Islington plans to introduce a 20mph across most of its roads.

So far, 20mph zones have been introduced in large areas of cities in England such as Oxford and Hull, while Glasgow City Council is also planning to adopt the measure in residential areas.