Scientists have disagreed over the pros and cons of using speed bumps to calm traffic outside schools.
Researchers have previously found that braking before and accelerating after speed bumps – or humps – can increase exhaust emissions.
Alastair Lewis, professor of atmospheric chemistry at the University of York, told the Daily Telegraph: ‘There is a road safety benefit to road humps, but they were not introduced with air quality in mind. They almost certainly reduce air quality.
Speed bumps remain contentious
‘The constant braking and accelerating required to go over road humps would not seem the best method of traffic calming to use outside schools.’
But another expert suggested that the evidence supported the use of speed bumps.
Ian Colbeck, professor of environmental science at the University of Essex, told the paper: ‘Road humps do increase the amount of oxide emissions, which are harmful, both from petrol and diesel, as a result of acceleration and deceleration.’
However, he said: ‘My view is that the pros of reducing the speed of vehicles outside schools outweigh the danger of the increase in harmful emissions. But ideally you should stop cars going past schools all together, because of the risk of both accidents and pollutants.’
A Department for Transport spokesperson said: 'Improving the UK’s air quality and cutting harmful emissions is a priority for this government.
'Traffic calming measures are a matter for local authorities and it is for them to decide which measures to use depending on local circumstances.'