Effectiveness of smart motorway safety technology being called into question

Cars on the M25

Evening traffic on the M25

Smart motorways were designed to increase capacity and reduce congestion during busy road times. Methods like using the hard shoulder as a running lane and variable speed limits are used to control the flow of traffic.   

However, the Office of Rail and Road (ORR) has found that the safety technology used to monitor smart motorways is not working as effectively as it should be.  

What is the technology? 

National Highways, the company in charge of maintaining English motorways and major A roads, has fitted Stopped Vehicle Detection (SVD) technology across all smart motorways after public concerns about safety. However, the ORR says the system has missed performance targets in every region. 

SVD uses radar technology to detect vehicles that have stopped for reasons other than heavy traffic. The vehicle is analysed by the software and an alert is sent to the control room, detailing the exact location of the vehicle. Operators can then make quick decisions regarding lane closures and altering speed limits to prevent accidents. 

Only one of National Highways five regions detected stopped vehicles in the target time 20 seconds or less, with other regions taking over a minute on average to alert to stopped vehicles. This delay increases the risk of accidents, particularly on smart motorways where all lanes are live.  

Increased safety concerns 

ORR said that false alarms were “substantially above the required maximum” at 75%, and further analysis of figures from the Midlands shows that five out of six alerts were incorrect. 

In other regions, figures show that less than three in five stopped vehicles were flagged by the system – overall one third of stopped vehicles were missed by SVD technology. 

These false, and missed, alerts create more work for operators, who must manually check what the system should be able to do accurately. It also reduces drivers’ confidence in smart motorways as any alert, real or otherwise, automatically triggers ‘Report of Obstruction’ notices on message signs around the reported location. Messages like this run the risk of increasing traffic congestion if they turn out to be false. 

John Larkinson, ORR’s chief executive, said: “Smart motorway data has shown that these roads are as safe as the motorways they replaced but the number of live lane breakdowns are higher.”  

Technology introduced too soon 

The rollout of SVD technology actually came ahead of schedule. But now, after the results of ORR’s report, many road safety bodies are questioning whether the technology was tested fully

AA president, Edmund King, said “If there are doubts about the technology, then the motorways are not smart and we should revert to tried and tested methods.” in response to the number of people left vulnerable after their vehicle has broken down in a live lane.” 

Meanwhile, Steve Gooding, the director of the RAC Foundation, responded to the report saying: “Whilst it is good news that stopped vehicle detection has been rolled out ahead of schedule, it will remain a concern that it hasn’t yet been fine-tuned to do as much good as it should.” 

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