Written evidence submitted by Professor Nick Reed,
Founder, Reed Mobility (RSM0046)


Reed Mobility is an independent transport consultancy, founded by me (Nick Reed) in 2019 to deliver projects that make transport systems safer, cleaner, more efficient, more ethical and more equitable. With an academic background in psychology, I led human factors research using driving simulators at TRL (the UK’s Transport Research Laboratory) for more than ten years, including the first study investigating driver behaviour in response to use of the hard shoulder as an active traffic lane in 2004 (as part of safety case for opening the M42 Active Traffic Management pilot scheme). I subsequently completed many studies that investigated drivers’ subjective and behavioural responses to different forms of hard shoulder running and associated road configurations. In 2011, I gave written and oral evidence to the Commons Transport Select Committee on the use of managed motorways, contributing to the committee’s report “Out of the jam: reducing congestion on our roads”. My work at TRL (2004-2017), as Head of Mobility R&D at Bosch (2017-2019) and at Reed Mobility (2019-) continues to examine how technology can improve our transport systems.

Reason for submitting evidence

The reason for submitting evidence is that Smart Motorways have understandably become a tremendously emotive topic. However, whilst every fatality is a tragedy, when we consider deaths across the road network, it is clear that there are other types of roads on which the risks of serious injury are much greater. The focus on Smart Motorways could detract from addressing those more urgent risks. Measures taken to mitigate the risk of collisions on Smart Motorways might divert resources that would have been more effective applied elsewhere and may reduce the overall capacity benefits that the Smart Motorway programme continues to deliver.


In 2004, a report from the National Audit Office criticised the Highways Agency (Highways England from April 2015) for lack of innovation by not introducing hard shoulder running on UK motorways, citing the successful use of such schemes in The Netherlands and Germany and the associated capacity increases that it provides. Its implementation in the UK soon followed with the first scheme known as the M42 Active Traffic Management (ATM) pilot. This used overhead gantries at 500m spacing along the carriageway and upon which were mounted Advanced Motorway Indicator signs (AMIs) above each lane to indicate its status. When appropriate to do so (based on a number of criteria), the hard shoulder could be opened as a running lane, indicated by text on MS4 matrix signs and the presence of a speed limit sign on the AMI over the hard shoulder. This ability to change the operational regime of the motorway was called ‘dynamic hard shoulder’ (DHS).

Hard shoulder running is supported by emergency refuge areas (ERAs) at regular intervals and technology to manage and monitor traffic flows and respond to incidents. When variable speed limits are in place but the hard shoulder is not open to traffic, a red X is shown above the hard shoulder. I led a project at TRL in January 2004 on the M42 ATM pilot, testing the concept in a driving simulator as part of the safety case for the scheme ahead of its real-world debut. It evaluated the effectiveness of the red X symbol to indicate that the hard shoulder was not available to traffic as a running lane (compared to a blank AMI). Whilst the observed behavioural differences were slight, participants subjectively preferred the clearer reinforcement of lane status afforded by the use of the red X. This was part of a programme of work that TRL delivered alongside projects awarded to other contractors to help Highways England evaluate and refine the concept.

The ATM pilot scheme evolved into a broader concept for wider implementation called ‘Managed Motorways’, which then became known as Smart Motorways. The motorway designs also evolved. Rather than opening the hard shoulder as an active traffic lane (DHS), more recent Smart Motorway schemes see the hard shoulder permanently converted into a running lane so that a three-lane motorway with hard shoulder becomes a four-lane motorway with ERAs. Instead of using gantries and matrix signs to indicate that the hard shoulder is open, these technologies are used to indicate circumstances in which a lane (or lanes) are closed – such as the presence of a stopped vehicle in a live lane. Rather than DHS, these are known as ALR schemes (All-Lane Running). Whilst drivers in our simulator studies tended to use DHS schemes correctly, I agree with Highways England’s position that the ALR configuration is more intuitive for drivers than DHS, which suffers from drivers’ being potentially unsettled by breaking normal conventions not to cross a solid white line.

Critics of smart motorways focus on the absence of the hard shoulder as a refuge for motorists breaking down, meaning that an inoperable vehicle can be stranded in a live running lane – with the obvious risk that other drivers unaware of the presence of the stopped vehicle may crash into it at motorway speed. By extension, this also poses a potential risk to recovery operatives tasked with rescuing vehicles in live lanes.

Without the permanent presence of a hard shoulder, it is vital that obstructions on Smart Motorways are detected and that responses are instigated as quickly as possible. This includes closing affected lanes but also reducing speed limits and deploying Highways England traffic officers to help manage the situation. Whilst there is CCTV coverage and traffic monitoring technologies to support this, it is surprising that stopped vehicle detection (SVD) systems were not a mandatory component of Smart Motorways from day one.

It is also apparent that prefixing motorways with the label ‘Smart’ is contentious for the public when, due to negative coverage of the schemes, they perceive the removal of the hard shoulder as adding risk to their journeys. I am not aware of the reasons for the name change from ‘Managed Motorways’ to ‘Smart Motorways’ but perhaps reverting to this previous name as part of the introduction of additional safety measures (such as comprehensive SVD, more cautious application of dynamic speed limits etc.) may be advisable as a more neutral designation.

There are many reasons why the Smart Motorway approach makes sense. One argument is that modern vehicles are more reliable (certainly more so than when motorways were first introduced) so breakdowns are rarer. Indeed, Highways England research has found that up to 90% of stops on the hard shoulder are for non-emergency purposes – including inappropriate uses such as toilet breaks, running out of fuel, reading a map and making a non-urgent call. Removal of the hard shoulder reduces the temptation of drivers to risk these improper stops. Genuine emergency stops within the ERAs are safer by giving greater separation from live running lanes and from the monitoring that can help manage traffic in the vicinity of the stopped vehicle. With genuine stops being so infrequent, conversion of the hard shoulder makes efficient use of land space, with capacity of a three lane motorway with a hard shoulder increased by a third with conversion of the hard shoulder to a running lane.

Whilst motorways are our safest roads, they are not risk free. They are inhabited by a mixture of vehicle types driven by people of all ages with a range of different driving experience, in a variety of alertness states and some travelling at more than 30m per second and with a stopping distance the length of a football pitch. However, breaking down in a live lane is not an exclusive occurrence on Smart Motorways. A sudden breakdown when travelling in the outside lane of a busy motorway could render a vehicle unable to reach the hard shoulder. Furthermore, breaking down on a dual carriageway (where traffic can travel at similar speeds as on a motorway) presents a potentially greater danger through since they do not have a hard shoulder, designated refuge areas, monitoring technologies or the ability for traffic management systems to adjust speed limits dynamically. However, drivers do not seem to hold the same negative perceptions for dual carriageways as they do for Smart Motorways.

A reasonable challenge to Highways England is why, through its operational management of strategic roads, does it get to decide how risks are traded on the network – in this instance trading the predicted increase in collision risk with a stopped vehicle in a live lane on a Smart Motorway against the safety gains that the additional ‘smart’ features included in such road designs. However, Highways England has the responsibility to provide a safe and effective strategic road network that is fit for purpose by making efficient use of public money. In the same way that the Department for Transport makes reasonable, evidence-based judgements about speed limits, blood-alcohol limits or vehicle designs, Highways England has to decide how to balance the requirement to maximise capacity within the available infrastructure and resources at its disposal whilst ensuring risk is as low as is reasonably practicable.

As far as I am aware, statistics tend to indicate that Smart Motorways are no less safe than the safest roads on the network. Whilst we should seek to understand all sources of risk on our transport system, the scrutiny being placed on Smart Motorways is at the expense of considering the wider risks associated with road use – in particular, collisions on other parts of the network (of which there are many more) and the emissions caused by motor vehicles (the devastating impacts of which are being increasingly recognised). By continually singling out Smart Motorways, its critics fail to recognise that the risks and issues are greater on other roads. If they turned the spotlight onto those risks, they might reveal concerns that are much more troubling and which could challenge the deeply ingrained apparent centrality of the car as society’s preferred mobility option.

The tendency to blame the infrastructure for collisions in live lanes on Smart Motorways also seems to divert attention away from the role of other drivers in a collision. Both ‘The Highway Code’ and ‘Roadcraft: The Police Driver’s Handbook’ emphasise the importance of the safe stopping distance rule:

Always drive so you can stop safely within the distance you can see to be clear on your own side of the road.

Adherence to this rule and applying reasonable standards of observation and anticipation would suggest that even if a collision could not be avoided, what may have been a fatal crash could be turned into an injury incident.

The implementation of Smart Motorways was a reasonable reaction to the initial criticisms raised by the National Audit Office. Already proven elsewhere, they offer cost effective increases in network capacity whilst attempting to mitigate the risks associated with turning the hard shoulder into an active running lane. However, they are not perfect. There is certainly more that could be done to ensure that vehicle stopped in live lanes are detected sooner and that traffic management measures are applied to help protect vehicle occupants and reduce the risk of collisions. There is also more that could be done to educate drivers about the need to remain alert and attentive and to allow reasonable space for possible hazards on the highway. However, if such measures are applied, I do not think that Smart Motorways schemes should be withdrawn.

Finally, whilst I advocate ensuring that existing Smart Motorway schemes are brought up to a minimum level of safety where live lanes are monitored appropriately and stopped vehicles are detected rapidly, my view is that the conversion of further motorways to the Smart Motorway format (beyond those where construction is already underway) should not proceed. At a time of climate emergency and with evidence mounting on the impact of poor air quality and noise on our health, we should focus our resources on ways to encourage those who have other options for any given journey should take them, with improvements and incentives to promote more sustainable modes of transportation.

(This evidence is an updated version of a post written by me and hosted on the Reed Mobility website at: https://www.reed-mobility.co.uk/reed-mobility-blog/smart-motorways-a-risk-worth-taking)


April 2021