The use of “smart” motorways has been controversial since their first introduction in 2006 by the then Labour government. With the issue of congestion acknowledged to cost the UK economy many millions of pounds every year, the scheme sought to ease the problem by employing the “unused stock” of road space on inside lanes, i.e. the hard shoulder. In combination with the latest technology, it was reasoned, smart motorways would be safe and make motorways more efficient, without the need to spend money on widening them. Criticised from the outset, the issue continues to be the cause of debate.

Operating Systems

Although conceived as a way of “freeing up” the hard shoulder, from the outset, smart motorways were never going to be as simple as this. As there is no physical change applied to any lane, the whole system relies on overhead displays, which are designed to implement Active Traffic Management (ATM). This means that, as long as road users follow the instructions, the number of lanes used and the speed limits on them can be varied, depending on demand. This, in turn, effectively means affecting changes during rush hours, bank holidays, etc. In theory, applying ATM should be no more difficult than was upgrading the technology used in the modern MOT test.

Using ATM, smart motorways can operate in three different ways. Firstly, “controlled” operation means keeping the hard shoulder as a refuge, while implementing varying speed limits in the other three lanes. Secondly, the “dynamic” mode opens the hard shoulder as a fourth lane at specific times, while also implementing a blanket 60 MPH speed limit on all four lanes. Finally, All Lane Running uses the hard shoulder as a true fourth lane at all times, in combination with altering speed limits.

Evidence Base

At the outset of the covid 19 pandemic and its subsequent restrictions, the government announced that it was planning to go ahead with the rollout of smart motorways. At the time, of course, road traffic was a tiny fraction of its normal levels, as people were told to stay at home (this was when the MOT test holiday was introduced). The announcement did not, however, actually relate to the ATM based smart motorway system; rather, the Department for Transport (DfT) proclaimed that all new smart motorways would make use of all lane running (ALR), at all times. This decision, they said, was informed by the best evidence available.

In fact, that evidence came from monitoring a mere 29 miles of such motorways. At the time of the announcement, there were already an extra 100 miles of ALR motorways in operation. Although not as hazardous as the dynamic mode of operation, all lane running has already been proven to increase road traffic incidents. Despite the very small evidence base, a 2020 freedom of information request showed that 38 people had died on ALR lanes since 2015. Such a scheme on one particular motorway witnessed an increase in near misses of 2,000% in the same period.

Technology Issue

From the outset, the “smart” in smart motorways has always meant dependence on technology. Active traffic management (ATM) acts in response to the number of vehicles on the roads at any one time; this then informs the illuminated above-lane notices which tell drivers what to do. With the introduction of the hard shoulder, either dynamically or permanently, another vital part of the technological picture is Stopped Vehicle Detection (SVD). This picks up any vehicle which has stopped moving; in the vast majority of cases, on the inside lane / hard shoulder. After detecting such a vehicle, the system is supposed to send a signal to the ATM to stop traffic using the affected lane.

There have been two instances, however, where SVD has been found wanting. In March 2022, a women driver died after her immobile car was smashed into by a van. In May, another van drove into the back of a broken down HGV vehicle, leaving the van driver seriously injured. Although a highways spokesperson said that SVD had reacted “within minutes”, this is clearly not good enough.

Ongoing Problems

The government has already gone back on its decision to roll out smart motorways, at least until 2025, while it “gathers more evidence”. Meanwhile, existing schemes are still in place, and work proceeds along other stretches of motorway as a result of expansions already in place. With continued incidents and adverse publicity, it is certain that the issue of smart motorways will not be resolved easily.