Many drivers who are caught speeding or going through red lights are not being prosecuted, according to a new investigation.
BBC Radio Four found that London is especially bad for failing to prosecute drivers - around 500,000 people are caught on camera each year, but one third of these cannot be traced to an address.
Sometimes this is because the vehicles are foreign, or they are not registered with the Driver and Vehicle Licensing Agency, but the programme also found evidence that some drivers were registering cars at other addresses to avoid being prosecuted.
Other reasons include cameras capturing emergency vehicles or faults with the cameras themselves - in February, whatcar.com reported evidence that up to 50% of speed cameras in England could be defective.
Road safety groups are angry that so many seem to be evading prosecution. Sarah Fatica, general manager at Brake, the national road safety charity, said: 'We are appalled to learn that technical faults with cameras and problems with untraceable vehicles mean that drivers are getting away with speeding and going through red lights.
'If drivers think they won't be punished if they are caught speeding, they may continue to speed and more lives will be put at risk. It is vital that speeders are duly punished and all drivers are encouraged to drive responsibly, sticking to the lifesaving limits.'
A 2004 Government report shows that speed cameras in the UK reduce deaths and serious injuries by more than 40% at camera sites. Speed is a contributory factor in a third of all fatal crashes.
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