A third of the individual systems designed to detect stopped vehicles on smart motorways that were tested last year failed to meet National Highways’ minimum detection rate, new data shows.
The Office of Road and Rail’s (ORR) third annual assessment of safety on the strategic road network (SRN) assesses the company’s wider safety performance and specifically its work to improve smart motorway safety.
The report states that extensive roadworks to build additional emergency areas on all lane running smart motorways saw technology at many locations turned off to avoid interference from the works and stopped vehicle detection (SVD) technology was tested at just 12 locations, compared to 21 previously.
The ORR said the data shows that, at a national level, the SVD technology continues to meet the performance requirements set by the company, although the data shows that the annual detection rate fell from 89% in 2023 to 86% in 2024, against a target detection rate of 80%.
In fact, four of the 12 schemes tested fell below even this relatively low benchmark, with one installation missing one in three stopped vehicles.
The four schemes were M6 Junctions 13-15 (74%); M56 Junctions 6-8 (78%); M62 Junctions 18-20 (71%); and M1 Junctions 13-16 (69%).
As Highways reported last year, five of the 21 (one in four) schemes tested in 2023 fell below the 80% minimum. The ORR pointed out that two schemes had failed to meet the minimum standard two years running.
These were the M6 Junctions 13-J15, where the detection rate was and 78% in 2023; and the M1 J13-J16, where the detection rate was 76% in 2023, meaning that the performance of both schemes worsened.
While warning that data from individual schemes should be treated with caution, the ORR said the overall sample size of stopped vehicle events in 2024 (476 events) was only 16% less than in the previous year.
AA president Edmund King said: ‘Data released by National Highways shows that several sections of All Lane Running on the M1 have a higher KSI rate now than before the loss of the hard shoulder.
‘At the same time, a third of radar detection schemes tested failed to meet the standard – two of which failed and worsened in a 12-month period.
‘Shockingly, the M62 J10-12 had a system failure for almost a month. This loss of safety technology, which drivers have been asked to put their trust in, meant they were put in unnecessary danger.'
The ORR report also reveals that SVD on one scheme missed the target that ‘false discovery’ – i.e where an alert is sent without there being a stopped vehicle – should be less than 15% of alerts.
It has consistently reported that National Highways has a target of an average of 20 seconds for the system to send an alert; in fact, any alert sent after 20 seconds is considered a failure.
According to the ORR, one scheme failed to meet the 20 seconds average.
The regulator added that it also required National Highways to report on the percentage of stopped vehicles that were correctly detected within 20 seconds on the 12 schemes that were tested.
It said: ‘This shows that, of all stopped vehicles detected, 91% were detected within 20 seconds, compared to 92% in 2023.’ As this wording makes clear, this statistic does not describe the ‘percentage of stopped vehicles that were correctly detected within 20 seconds’ but vehicles detected within 20 seconds as a percentage of the sub-set of stopped vehicle events that were detected.
Even on this methodology, some schemes saw only four out of five detections taking place within 20 seconds.
A National Highways spokesperson said: ‘Our latest analysis continues to show that overall, smart motorways remain our safest roads.
‘We have completed all of our stocktake actions including upgrading the technology to detect stopped vehicles and improving response times to live lane breakdowns.
‘On top of this we have made good progress on the delivery of our commitment to install 150 new emergency areas.’
The ORR report explains that National Highways’ SVD system uses radar technology to detect stopped vehicles on ALR smart motorways and that the testing process uses CCTV footage from each scheme to measure performance over a 24-hour period.
The response of the SVD system to each stopped vehicle event is checked to determine whether the stopped vehicle event was correctly identified by the system and an alert issued, from which a ‘detection rate’ for each scheme can be calculated.
In fact, the new report corrects a mistake in the 2023 report, which presented ‘events’ as a sub-set of ‘alerts’, raising concerns that the data was skewed by the failure to include events where no alert was issued.
