When speed humps can kill
In browsing a semi-humorous article entitled ‘The 5 Most Popular Safety Laws (That Don't Work)’ that I found via Digg, I stumbled across a link relating to speed humps and how they impede response times for emergency vehicles.
Pretty obvious, you might think. But it was the extent of the problem which interested me and the irony behind the perception of their life-saving value – at least in some parts of the world.
The Chairman of the London Ambulance Service, Sigurd Reinton, recently claimed that speed humps are killing hundreds of Londoners by delaying 999 crews. He said “For every life saved through traffic calming, more are lost because of ambulance delays.”
There are about 8,000 heart attack victims in London every year, and London has a particularly poor survival rate. One reason is no doubt because even a small delay increases the death rate enormously. For example 90% of victims survive if treated within 2 minutes, but it falls to 10% if treatment is delayed for 6 minutes. So for every additional minute of delay caused, up to an extra 800 victims of cardiac arrest could die. This compares with a total of 300 people who die from traffic accidents.
Research in the USA supports these claims. One report from Boulder, Colorado suggests that for every life saved by traffic calming, as many as 85 people may die because emergency vehicles are delayed. It found response times are typically extended by 14% by speed-reduction measures.
Mark Belchamber examined the effect that speed humps have on paramedic response times and patient care in a thesis available here.
The study main consisted of asking 36 paramedics from different parts of the country for their experiences, and their response to humps. For example, 66% would deviate to avoid humps even when on emergency calls, and half of them were willing to add 2.5 minutes to the response time as a result.
88% of paramedics felt that speed humps interfered with CPR or other medical procedures. All respondents considered that a number of patient conditions were affected detrimentally by speed humps, particularly spinal or back injuries, and fractures generally.