Smart Motorways

Smart motorways are designed to better manage the traffic flow and prevent the traffic bunching that can lead to multiple accidents and/or slow journey times because of the traffic congestion that is caused.

The first conversion to a ‘smart' motorway was done on the M42 in 2006 - this involved variable speed limits. Smart Motorways are now fairly common in the South and Midlands.

The journey time statistics for smart motorways has shown reductions of over 25% in journey time; there are also benefits in terms of fuel consumption and pollution as well as a reported reduction in accidents.

There are three types of smart motorways:

1. Controlled motorways

Controlled motorways have three or more lanes with variable speed limits. The hard shoulder should only be used in a genuine emergency. Effectively these are simply motorways as we have always known them but with variable speed limits.

2. Dynamic Hard Shoulder Running schemes

Dynamic Hard Shoulder Running involves opening the hard shoulder as a running lane to traffic at busy periods to ease congestion.

Again these are like regular motorways, the difference being that there are lane indicators on the gantry signs over the hard shoulder to show whether it is available for normal driving or whether it is closed and should just be used for emergencies.

One of the worries about use of the hard shoulder as a running lane is as it will create problems in the event of breakdowns.

The first thing to note here is that cars are far more reliable than they used to be and so on less likely to break down - at least if they are maintained properly. In the event of a breakdown or other incident on the hard shoulder (now renamed as lane one) the gantry signs would display a red X symbol to close that lane.

The length of the controlled area is monitored by CCTV and so breakdowns and incidents can be identified quickly, even before the people involved called the emergency services. (Control Room)

3. All-Lane Running schemes

On All-Lane Running Smart motorways there is effectively no hard shoulder. The first section of motorway in the UK to become completely All-Lane running was the M25 between junctions 23 and 25.

The main difference between All-Lane Running motorways and the other types is that the solid line denoting the hard shoulder has gone. Lanes are all marked equally with broken white lines. The basic driving rule applies, namely to keep to the left lane and only change lanes to the right in order to overtake or to follow direction signs.

As with the dynamic hard shoulder these roads are monitored by CCTV and in the event of breakdowns or other incidents lanes can be closed from the control room by activating the gantry lights.

In the event of a breakdown

This is one area where our motorway teaching needs to change on roads with a dynamic hard shoulder and All Running Lanes.

The advice to drivers is to try to reach an emergency refuge area if they can do so safely. If this is not possible and there is no safety barrier, to try to move the vehicle onto the verge. Wherever possible drivers should still get out and wait on the motorway bank or other safe place away from their vehicle. 

There will be times when it's not possible to get out of the vehicle, perhaps because the car breaks down in one of the outer lanes cannot be moved to the left; in these situations drivers should call 999 (it's assumed that most people now have mobile phones), and keep their seat belts securely fastened.

Next: Defensive driving on motorways