Smart motorway radar misses a third of broken-down vehicles, says regulator

Smart motorways allow traffic to use all lanes to be used by traffic instead of having a hard shoulder. Photograph: Steve Parsons/PA

Safety technology on smart motorways is failing to work properly, the regulator has said, with one in three broken-down vehicles missed – and three in four detected in England proving to be false alerts.

National Highways has retrofitted stopped vehicle detection technology (SVD) across all smart motorways without a hard shoulder, after increasing public and political concern about safety.