Vehicle detection technology which is supposed to identify broken down cars on smart motorways is failing 40 per cent of the time, leaving motorists stranded and vulnerable to accidents.

A major investigation by the Daily Mail found that the Stopped Vehicle Detection (SVD) monitors only flagged 62 per cent of cars within 20 seconds, putting almost four out of ten cars outside of the safe time limit as set by National Highways.

The issue of allowing vehicles to drive on the hard shoulder of motorways is one which has courted controversial headlines since a number of fatalities were blamed on the system, when broken down cars were not spotted and were hit by moving traffic.

In addition to the problem with spotting vehicles within 20 seconds, a Freedom of Information request also revealed that the SVD was also producing errors in providing the correct location information, in almost one in five incidents.

The problems were revealed after an undercover reporter told of the major problems with the system at National Highways control centre and a subsequent FOI asked for the details on a secret report of incidents.

The report said: ‘Clearly, a prompt response is vital to the effective use of the SVD system, since earlier operator intervention will mitigate the risk presented by a stopped vehicle in a live lane.’ But the breakdown is yet another issue which is sure to add weight to the calls to end the smart motorway project forever.

“So-called “smart” motorways were sold to the public by National Highways on the basis that “if the worst happens, we will find you and keep you safe”,” said Jack Cousens from the AA.

“Shockingly, drivers are sitting ducks for longer than they should be. These figures show the system is woefully inadequate.”

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