Here we have outlined everything you need to know including what they are, where they are, how to use them and what to do if you breakdown on one.

What is a smart motorway?

A smart motorway is a section of a motorway that deploys traffic management methods to increase capacity and reduce congestion in particularly busy areas. These methods include using the hard shoulder as a running lane and using variable speed limits to control the flow of traffic.

Highways England (previously the Highways Agency) developed smart motorways to manage traffic in a way that minimises environmental impact, cost and time to construct by avoiding the need to build additional lanes.

There are three types of scheme which are classed as smart motorways.

What different types of smart motorway are there?

The three different types of smart motorway currently include: controlled motorways, dynamic hard shoulder running schemes and all lane running schemes.

All lane running schemes

As the name suggests all lane running smart motorways use the hard shoulder permanently as a running lane for traffic.

On Monday 14 April 2014 eight miles of the M25 between junctions 23 and 25 became England’s first smart section of motorway with traffic running permanently on a new running lane that was previously used as the hard shoulder and a further section of the M25 between junctions 5 and 6 opened a few days later.

Under all lane running schemes, lane one (formerly used solely as the hard shoulder) is only closed to traffic via overhead and verge mounted cantilever signs, in the event of an incident. On these sections broken white lines between all lanes indicates that each lane has the same status.

Just as in the dynamic hard shoulder schemes, overhead gantry signs display the mandatory speed limit which varies depending on the traffic conditions and speed cameras are used to enforce these. Signs can also be used to close lanes should that be required.

If an incident occurs in lane one – formerly the hard shoulder – a red cross (X) symbol is displayed to let motorists know the lane has been closed to traffic. Driving in a lane under which the red X symbol is being shown is illegal and could lead to you being prosecuted.

CCTV is used extensively to monitor traffic for any incidents. Should drivers break down or be involved in an accident there are emergency refuge areas at the side of the carriageway for them to use. These are typically further apart than current sections of motorway operating the dynamic hard shoulder running configuration, with an average spacing of 1.5 miles apart.

Controlled motorway

Controlled motorways have three or more lanes with variable speed limits, but retains a hard shoulder. The hard shoulder should only be used in a genuine emergency.

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. The scheme, which was initially developed on the M42 in the Midlands, is now in operation on sections of the M42, M1, M6, M4 and M5.

On these stretches a solid white line differentiates the hard shoulder from the normal carriageway. Overhead signs on gantries indicate whether or not the hard shoulder is open to traffic.

They also display the mandatory speed limit which can vary according to the traffic conditions. Speed cameras are used to enforce the variable speed limits.

If an incident occurs in lane one – formerly the hard shoulder – a red X symbol is displayed to let motorists know the lane has been closed to traffic. Driving under a red X sign is illegal.

The hard shoulder must not be used if the signs over it are blank or display a red X, except in the case of an emergency.

CCTV is used extensively to monitor traffic for any incidents. Should drivers break down or be involved in an accident there are emergency refuge areas at the side of the carriageway for them to use.

Where are smart motorways in the UK?

There are a number of smart motorways currently in use and many more planned or in development. Below is an up-to-date list of the current schemes.

All running lane locations

M62 J18-20

M6 J10a-13

M3 J2-4a

M25 J5-6/7

M25 J23-27

M1 J28-31

M1 J32-35a

M1 J39-42

Controlled motorway locations

M60 J8-18

M42 J3a-M40 J16

M1 J6a-10

M26 J16-23

M25 J10-16

M25 J18-10

M25 J7-8

M20 J4-7

M25 J2-3

M25 J27-30

M1 J25-28

Hard shoulder running locations

M62 J25-30

M6 J8-10a

M6 J5-8

M4 J19-20

M5 J15-17

M1 J10-13

M42 J3a-7 (pilot)

M42 J7-9

M6 J4-5

I've broken down on a smart motorway - what do I do?

If you are unlucky enough to break down or be involved in an accident while on a smart motorway, you should follow these steps:

• Use an emergency refuge area (ERA) if you are able to reach one safely. These are marked with blue signs featuring an orange SOS telephone symbol on them. Different types of smart motorways have different ERA spacing, but the furthest you will be away from one is around 1.5 miles. 
• If you cannot get to an emergency refuge area, you should try to move on to the verge if there is no safety barrier and it is safe to do so.
• In all cases, switch on your hazard warning lights.
• If you stop in the nearside lane, leave your vehicle via the nearside (left hand) door if it is safe to do so and wait behind the safety barrier, if there is one. If you are unable to move over to the nearside lane, remain in the vehicle with your seat belt on.
• If you can leave your vehicle safely, contact Highways England via the roadside emergency telephone provided in all emergency refuge areas. If it is not possible to get out of your vehicle safely, then you should stay in your vehicle with your seat belt on and dial '999' if you have access to a working mobile phone.

For advice on what to do if you break down elsewhere you might also want to refer to our general motorway breakdown advice.

Source: rac.co.uk