Written evidence submitted by Mr Martin Whale (RSM0083)

A major problem with the introduction of Smart Motorways is that there is too much involvement of human variability and fallibility, both on the roads and in the control rooms. There is too much reliance on road users driving as they should and not as many of them do. Relying on control room staff to watch TV monitors to spot incidents is unreliable as humans get distracted.

The task of identifying an incident or a stopped or rapidly slowing vehicle needs to be automated as technology does not lose focus on the task and will operate tirelessly 24/7.


The use of Red X to close one or more lanes is demonstrably flawed as without enforcement what happens in practice is that whilst some drivers confine themselves to the open lanes and usually begin to queue, others carry on until they reach the actual obstruction and then push into the head of the queue.  Not only is such queue-jumping frustrating for law-abiding drivers there is a safety risk introduced by the disparity of response. Some drivers are slowing to get into the open lanes whilst others are continuing at unabated speed.

When Red X is used the speed-sensing cameras should be switched on and more significantly the flash must also be activated. This will give a visible deterrent to drivers that there is potentially enforcement, even if the cameras don’t actually work. Once the first couple of vehicles have gone through the Red X and activated the flash those drivers following are far more likely to avoid going through. The flash must operate however low the speed so as to create the deterrent just as if there was a physical barrier across the lane at that point.


The use of all lanes running is a benefit when there is heavy traffic but when an incident does occur it is a significant disadvantage. When a vehicle develops a fault it’s not always possible to reach a refuge and there is huge danger in stopping in an active lane. Without technology to rapidly detect a slow or stopped vehicle and immediately introducing an enforced Red X behind the stranded vehicle the risk of collision is high.

In the event of a collision it’s likely that one or more lanes will be blocked. As soon as that occurs traffic quickly backs up and queues form in all lanes. The lack of a hard shoulder then causes major problems as there is no easy route to the incident for the emergency services. They take longer to arrive as they have to pick their way through the queues instead of having a clear route through to the incident. Potential life-saving response is delayed and the delays for those in queues are far longer than they might be with a hard shoulder available.


A major safety issue on any busy motorway is the difficulty of seeing what is happening ahead. Its not possible to see through many vehicles so drivers can often only see at best a few vehicles ahead of them, particularly on straight sections -on a curving road you can see past the side of vehicles in front. The lack of visibility is compounded by the practical difficulty of leaving the desired safe space between vehicles. Too many drivers are prepared to push into a space so long as there is just a few metres to spare, so if you try to leave a gap it gets filled by such a driver and you then have to back off to create the gap you would like to leave. The process repeats and other drivers will undertake because you are not “keeping up with the vehicle in front”. Like it or not drivers are forced to drive closer to the vehicle in front than they would like, just to avoid being ‘cut-up’. It shouldn’t happen if everyone drove according to the highway code, but it does.

In the light of the way many drivers actually use the roads the concept of the variable speed limit system is fundamentally flawed. Whilst it may make sense to an academic that drivers should slow down because the control room can see slower traffic in the distance, this relies on everyone understanding and complying. As with Red X, in practice some drivers will slow whilst others will continue until they see the brake lights and slower traffic. Again this causes hazardous speed disparity. Given that a vehicle can stop completely from 70mph comfortably within 150 metres, its understandable that drivers don’t readily see the need to slow down when they can see traffic still moving half a mile ahead.

On all other roads this is the way drivers operate – they respond to what they can see happening just a few seconds ahead, not half a minute away. To change the concept on “smart” motorways to one where a control room operator is telling you what speed to drive at is a dangerous change in the mentality. It relies on drivers changing their attitude and having total trust in the signs. In my own experience I have found that several times the variable speed limits are in use but there is no hazard. Whether its caused by a technical fault or fallible control room staff, It only takes one or two examples of this “cry wolf” false use of the system to undermine confidence in it.

Rather than the variable speed limit concept what should have been introduced is a “Speed Information System”.  Given the difficulties of seeing what is happening on the road ahead, the overhead gantries are something that can usually be seen some way ahead. If each of these were set to display the speed of traffic 300 metres ahead then this would provide usable, reliable real-time information for drivers. It would supplement the normal method of driving rather than changing it (as variable limits do). It wouldn’t need the involvement of control room staff as the technology would simply continuously measure traffic speed and display it further back along the road. The system could be supplemented by flashing lights that activated when the system detected speed dropping significantly.

A system that gave reliable and timely information for drivers to respond to is far more likely to be trusted and result in the majority reacting in the same way, all slowing together safely, rather than the mixed response to the variable limit system.

The system could also be set to detect a rapidly slowing or stopped vehicle, due to the change in speed between one sensor and the next. It would be able to create a warning for oncoming drivers and flag up to control room staff the need to view that section of road.


April 2021