Highways Agency - Safe roads, Reliable journeys, Informed travellers
What is Active Traffic Management?
On 12 September 2006, motorists on the M42 in the West Midlands were the first in the country to be able to drive on the hard shoulder during busy periods as part of a scheme aimed at cutting congestion.
The scheme, called Active Traffic Management, is between junctions 3 and 9 and directs drivers to use the hard shoulder during times of peak congestion using electronic signs above each lane. Together with variable speed limits, which help smooth the flow of traffic, the scheme has had great success in reducing congestion on the M42.
Safety was of critical importance during the design of the scheme and emergency refuge areas are provided at regular intervals to provide motorists with a safe place to stop away from the traffic in the event of problems with their vehicle. These refuge areas are linked by telephone and CCTV cameras to the nearby regional control centre.
The Highways Agency also worked closely with the emergency services to help them access the motorway in the event of an incident. Highways Agency control room staff have access to over 200 cameras on the 11 mile stretch, allowing them to easily spot any incident as it occurs. They can then close any individual lane or lanes by putting a red 'X' on the electronic signs above the lane(s) affected. This will then protect the vehicles involved in the incident as well as clearing the lane to allow emergency vehicle access.
Compared with road widening, Active Traffic Management is significantly more cost effective but provides comparable benefits including increased capacity, reduced journey times, increased journey time reliability, lower emissions and lower fuel consumption.
Please also let us know what you think of Active Traffic Management by filling in our feedback form.
Please take the time to read the following pages and find out more about how Active Traffic Management works and some of the benefits it provides. You can also take an interactive drive-through of the scheme.
This animation describes how Active Traffic Management works in practice.
Results from the M42
The use of hard shoulder running on the M42 has shown that innovative thinking can help cut congestion.
Initial fears from safety campaigners have proved unfounded as the number of accidents on the stretch has actually decreased - the accident rate went down from 5.1 a month to 1.8 a month. 
As well as the decrease in the accident rate, the first twelve months of the trial on the M42 have seen other significant benefits for motorists, the environment and the economy. Use of the hard shoulder in peak periods saw average journey times fall by more than a quarter on the northbound carriageway and drivers' ability to predict their weekday journey times improved by 27%. Alongside this, overall fuel consumption reduced by 4% and vehicle emissions fell by up to 10%.
The scheme is also very popular with motorists, with 68% saying they felt more informed about traffic conditions and 60% saying that they would like to see it extended elsewhere on the motorway network.
To find out more about the M42 results please visit the Highways Agency Research Compendium.
The Birmingham Motorway 'Box'
The success of Active Traffic Management on the M42 means that the Highways Agency has been asked by the Department for Transport to extend the scheme to some of the motorways around Birmingham, colloquially known as the Birmingham Motorway Box.
The extension of Active Traffic Management incorporates variable speed limits and hard shoulder running in two phases and in the following locations:
Phase 1
- M40 junction 16 - M42 junction 3A - variable speed limits to control the speed and flow of the traffic as it approaches the current Active Traffic Management stretch. This will help prevent the breakdown of traffic flow as the motorways merge.
- M42 junction 7 - 9 - variable speed limits to control the speed and flow of traffic as it leaves the current Active Traffic Management stretch. This will help smooth the flow of traffic leaving and joining the M42 for the M6 and M6 (Toll)
- M6 junction 4 - 5 - variable speed limits and hard shoulder running. This is a very busy stretch of the M6 and will benefit from an additional lane at busy times, making hard shoulder running an ideal solution. The section between 4A and 4 southbound will use variable speed limits only, and not hard shoulder running.
Phase 2
- M6 junction 8 - 10A - variable speed limits and hard shoulder running. This stretch of the M6 between the M54 at junction 10A and the M5 at junction 8 is one of the busiest stretches of motorway in the whole country and will benefit from an additional lane at busy times, making hard shoulder running an ideal solution.
Work on the £150m scheme began in Autumn 2008 and work on phase two began in early 2009. Phase one was completed in November 2009 and phase 2 is scheduled for operation by Spring 2011. We are looking to keep three lanes open during the road works in busy periods although occasional weekend and evening closures will be necessary.
Where next for hard shoulder running?
On 25 October 2007, the Secretary of State for Transport announced a feasibility study into how ATM technologies and other advanced signalling and traffic management techniques might be applied more widely across the motorway network to cut congestion and benefit road users. More information is available on the Department for Transport website.
In March 2008, this feasibility report identified stretches of motorway across England that could benefit from active traffic management-type technology and work is now underway to develop proposals for these locations. More information is available on the Department for Transport website.
Safety - breakdowns
Safety was at the centre of the design of Active Traffic Management and we worked very closely with the recovery industry during the development of the scheme.
Emergency refuge areas have been provided at regular intervals for use in case of emergency or breakdowns. These are fitted with the latest emergency roadside telephones, linking you directly to our regional control centre at nearby Quinton. These telephones are positioned behind safety fencing and at a height suitable for disabled road users. They also have a text messaging facility in eight different languages for both the hard of hearing and foreign drivers. The emergency refuge areas are also covered by CCTV so the operator can see you as soon as you enter the refuge area.
The refuge areas are wider than the hard shoulder, providing additional safety for you and anybody working on your vehicle, such as a recovery operator.
For your safety you should always contact the control centre, via the emergency telephone, to gain advice on safely exiting a refuge area. Exiting the refuge area may require support from the control centre, particularly if you are driving a slow moving or large vehicle. In some circumstances it may be possible for the control room operators to close the hard shoulder in order to allow you to exit the ERA safely. 
Safety - emergency vehicle access
Safety was at the centre of the design of Active Traffic Management and we worked very closely with the emergency services during the development of the scheme.
The proximity of the gantries on Active Traffic Management makes for a very flexible motorway - operators at the control centre have the ability to open and close any lane of this stretch of motorway at the touch of a button. The extensive CCTV coverage also means that the operators will spot any incident very quickly and take appropriate action
In the event of an incident the operators can simply close the affected lane(s) by putting a red cross on the electronic signal above the lane. This means that the lane is clear for emergency vehicle access and traffic can still make it past the scene using the unaffected lanes. The electronic message signs will also make sure that drivers have the latest information on any road closures.
Results from the M42 have actually shown a decrease in the number of accidents - the accident rate went down from an average 5.1 a month to an average 1.8 a month.
How does it work?
The main purpose of Active Traffic Management (ATM) is to manage congestion. It can however also be used to manage the traffic around incidents on the motorway.
The two main components of ATM are variable speed limits, or controlled motorways, and hard shoulder running.
During normal motorway conditions, with no incidents or congestion, all the electronic signs will be blank and all normal motorway rules apply.
As congestion begins to build up, or an incident is detected, the sensors underneath the road surface will detect slower moving traffic and the computer system calculates the most appropriate speed for the traffic. This speed limit will then appear on the overhead signals, with a red ring surrounding the number indicating that it is a mandatory speed limit. A red cross will appear over the hard shoulder indicating that the lane should not be used except in the event of an emergency or breakdown.
By reducing the speed on the motorway we are able to smooth the flow of the traffic, reducing stop-start driving conditions. Reducing speeds also helps prevent breakdown of traffic flow and increases traffic throughput. The uniform speed across all three lanes also reduces the need for drivers to change lanes.
If congestion continues to build up the sensors will alert operators in the regional control centre that hard shoulder running may now be appropriate. The operator will then be taken through a semi-automated system using CCTV cameras to check the hard shoulder is free of debris and vehicles. From the first alert the hard shoulder between any two junctions can be opened within minutes, giving an extra running lane to provide additional capacity at the busiest times of day.
When the hard shoulder is open to motorists a speed limit appears on the electronic signal above the hard shoulder. The speed limit will be the same across all four lanes, again reducing the need for drivers to change lanes. A message will also appear on the electronic driver information signs to inform motorists that the hard shoulder is available for use. In the event of an emergency or breakdown, you should use one the emergency refuge areas.
For further details on what happens in the event of an emergency or breakdown during hard shoulder running please visit our safety pages.
What's different to a normal motorway?
Drivers on the M42 will have noticed the following changes since Active Traffic Management was introduced.
Lightweight Gantries
These support the technology that makes ATM possible. They carry cameras as well as electronic signs and signals to show drivers which lanes are available, the current speed restriction and warnings of any incidents or congestion ahead.
Lane Specific Signals
There is one of these signals above each lane. They inform drivers of the current mandatory speed limit as well as showing which lanes are currently open.
Driver Information Signs
These warn drivers of congestion or incidents ahead. They also now include internationally-recognised pictograms to help drivers recognise quickly what is happening ahead of them.
Digital Enforcement Technology
Purpose-built digital safety cameras are used to enforce the mandatory speed limits.
Entry/Exit signs
Signs have been erected to inform drivers when they are entering or leaving an Active Traffic Management area
Emergency Refuge Areas
Positioned adjacent to the hard shoulder, these are safe areas away from the traffic for use in the event of a breakdown or emergency. They are wider than the hard shoulder to provide additional safety and are connected to our regional control centre in nearby Quinton by both CCTV cameras and emergency roadside telephones. In the event of a breakdown when the hard shoulder is not in use as a running lane, you can still use the hard shoulder in the event of a breakdown, as outlined in the Highway Code. We would however recommend that emergency refuge areas are used for all breakdowns and emergencies as, because they are away from the main carriageway, they offer additional protection.
Emergency Roadside Telephones
These are situated in every single emergency refuge area and offer a direct link to our regional control centre at nearby Quinton. They are the latest model telephone and have foreign language and text facilities.
CCTV Cameras
Comprehensive CCTV coverage of this stretch of motorways helps operators open the hard shoulder safely as well as allowing them to spot incidents quickly.
Full Motorway Lighting
This provides a safer driving environment at night and in bad weather as well as allowing operators to see the motorway on CCTV during darkness.
Sensors
Electronic sensors are buried in the road surface to measure the general speed and flow of traffic. The sensors are used, via a computer system called MIDAS (Motorway Incident Detection and Automatic Signalling,) to automatically set the most appropriate speed limit for current traffic conditions.
What do the signs mean?
The electronic signs and signals on Active Traffic Management let you know about traffic conditions on the road ahead as well as the current speed limit and availability of individual lanes. It is important to comply with the signs in order to make your journey safer and more reliable.
You may see the following signs whilst driving on an Active Traffic Management stretch of motorway.
Blank signal
This is applicable to all lanes, including the hard shoulder, and means that normal motorway rules apply. The hard shoulder is only for use in case of an emergency or breakdown.
Mandatory speed limit
This is applicable to all lanes, including the hard shoulder, and means that this is the maximum permitted speed. The speed will be enforced by digital enforcement cameras.
White arrow with flashing beacons
This sign is applicable to all lanes, including the hard shoulder, and means that you should move into the lane as directed
Red cross with flashing beacons
This sign is applicable to all lanes, including the hard shoulder, and means that you must not proceed any further in this lane.
Red cross without flashing beacons
This sign is applicable to the hard shoulder only and means that you should only use the hard shoulder in an emergency or breakdown, as per the Highway Code.
National speed limit
This sign is applicable to all lanes, including the hard shoulder, and means that national speed limits apply.
Cameras
The Highways Agency has installed over 200 cameras on the M42 Active Traffic Management stretch. There are four different types:
Pan, Tilt and Zoom (PTZ) CCTV cameras
There are 19 PTZ cameras on the M42 which are used by staff in our regional control centre to identify and monitor incidents and congestion. The position and zoom of the camera are controlled remotely from the control room and provide comprehensive coverage of the scheme.
Fixed CCTV cameras
There are 153 fixed CCTV cameras focused on the hard shoulder of the 17km ATM stretch of the M42. These are used by staff in our control room to ensure the hard shoulder is clear of debris and vehicles prior to opening. Once the hard shoulder is opened they are used to monitor incidents and congestion.
There are also 39 fixed CCTV cameras focused on emergency refuge areas to enable staff to provide assistance in the event of an emergency or breakdown.
Automatic Number Plate Recognition (ANPR) cameras
ANPR cameras are used by our monitoring consultants. They allow them to track where individual vehicles join and leave the motorway and how long their journey took. This is important information which allows us to assess the success of the scheme. The information is encrypted so at no stage do our monitoring consultants have any access to personal information.
Digital Enforcement Cameras
These are used by West Midlands Police to ensure compliance with the overhead signals. Compliance is important to the safe and effective operation in reducing congestion. The cameras are digital and therefore do not require wet film. They were designed specifically for use with variable speed limits.
M42 Background Information
Construction on the M42 began in Summer 2003. It was introduced in three phases, with advisory speed limits coming on board in Winter 2004. These speed limits became mandatory in Winter 2005 and hard shoulder running began in September 2006.
The M42 between 3A and 7 was chosen because of its strategic importance as it links the M40, M6 and M5 motorways. The route carries up to 140,000 vehicles a day including long distance national traffic, local traffic using business parks and residential areas and seasonal traffic using Birmingham International Airport. The motorway also experienced heavy congestion at points where traffic leaves and joins the motorway and an above average accident rate, particularly between junctions 5 and 6.
Two Statutory Instruments were drafted to modify existing regulations to allow the ATM project to succeed. These regulation changes became law on 27 July 2005.
Frequently Asked Questions
Q: Why do I see 60/50mph speed limits set when there are low levels of traffic and the traffic appears to be moving freely?
A: This often happens after a period of congestion on the motorway and the traffic conditions are recovering. By limiting the speed of traffic as conditions improve, we decrease the likelihood that the traffic flow will break down in stop start conditions again.
Q: Why do I sometimes see inappropriate signals and messages on the gantries?
A: The system is responding to a real event that is happening at that moment. It is possible that by the time you arrive at the location of the original incident it has cleared and you will not be able to see the original cause. It's also possible that traffic could have been caused by somebody braking hard and causing a concertina effect back along the motorway, meaning the system would trigger because of congestion but you would never see the original cause.
Q: Will I be able to reach an emergency refuge area if I break down?
A: Due to the close proximity of the ERAs it is highly likely that you would be able to reach one in the event of a breakdown. If you were not able to guide your vehicle into an ERA either during normal motorway conditions or hard shoulder running then you should follow the advice in the Highway Code.
Should this happen, our controllers will be able to spot you on CCTV camera and use the overhead electronic signals to close the lane you are in to protect you and provide access for your recovery operator. One of our Traffic Officers may also be on hand to help you into a refuge area.
Q: How do the emergency services reach the scene of an accident if the hard shoulder in use?
A: The operators at the control centre have the ability to open and close any lane of this stretch of motorway at the touch of a button. This means that in the event of an incident they can simply close the affected lane(s) by putting a red cross on the electronic signal above the lane. This means that the lane is clear for emergency vehicle access and traffic can still make it past the scene using the unaffected lanes.
M42 Junction 5 Hard Shoulder Through Junction Running
M42 Junction 5 Southbound Part Time Hard Shoulder Through Junction Running
How does Part Time Hard Shoulder Through Junction Running work?
This forms part of the Active Traffic Management project on the M42 between junctions 3A and 7. The section of Through Junction Running at Junction 5 southbound operates in the same way as the rest of the scheme. Drivers are authorised to drive on the hard shoulder when a speed limit is displayed over it. Only when a speed limit is on display can drivers use the hard shoulder as a running lane. This is exactly the same as the arrangements elsewhere between Junctions 3A and 7. See also How does it work? for more information about Active Traffic Management.
Variable Message Signs, along with the Advance Direction Sign approaching the junction, and a sign on the slip road onto the motorway, tell drivers which lanes are open for use.
Approaching the junction, the Advance Direction Sign located at the junction indicates which lanes are open for which destination.
Figure 1 - Advance direction sign at Junction 5 Southbound showing that the hard shoulder is open to traffic travelling through the junction.
When the hard shoulder is open to traffic through the junction area, lane arrows show that all four lanes may be used to continue along the M42. The turn onto the A41 to Solihull is shown in the top section of the sign.
Figure 2 - Advance direction sign at Junction 5 Southbound when that the hard shoulder is closed to traffic through the junction.
At all other times, the sign shows three lanes available for M42 traffic with the inside lane for the A41 only.
The large Variable Message Signs located on the gantries help drivers to know which lanes are open on the road ahead of them. These signs show dynamically which lanes are open approaching the junction, travelling through the junction or joining the motorway at the junction.
Approaching the junction, when the hard shoulder is open to traffic upstream between Junction 6 and Junction 5 or between Junction 6 and Junction 4, legends indicate whether the hard shoulder through the junction is open to traffic.
Figure 3 - Schematic of Sign legends approaching the junction, showing the hard shoulder closed through the junction (left hand image), or open (right hand image).
At the merge where traffic joins at Junction 5, the signs provide clear advice to drivers on which lanes are currently open to traffic. In addition to showing whether or not the hard shoulder downstream of the merge is open to traffic, when the hard shoulder is closed the signs show the distance in yards to the end of the auxiliary lane.
Figure 4 - Schematic of Sign legends at the merge, showing that hard shoulder is open downstream
Figure 5 - Schematic of Sign legends at the merge, showing that the hard shoulder is closed downstream
How do I leave the motorway at Junction 5?
Drivers wanting to use the junction leave the motorway from the inside lane as now.
What about joining the motorway?
When joining the motorway, drivers travelling down the slip road see a verge mounted Fixed Text Message Sign (FTMS), which shows whether the hard shoulder is open to traffic travelling through the junction.
Figure 6 - FTMS showing the hard shoulder through the junction open to traffic (left) or displaying a grey background (right) at all other times
When the hard shoulder is open to traffic, drivers merge at the bottom of the slip road into traffic coming along the hard shoulder. They are reminded of the need to give way by a broken white line at this point. Drivers can then accelerate in the auxiliary lane. When the hard shoulder is open between Junction 5 and Junction 4, they can remain in this lane and then use the hard shoulder. When it is closed, drivers have until the end of the auxiliary lane to merge across into the existing motorway traffic. This auxiliary lane is 620m in length, allowing plenty of time and space for drivers to move into the appropriate lane for their journey.
What should I do if I break down?
Always remember that motorway hard shoulders are for emergency use only and you should only stop there if it is a real emergency and you have no other choice. Try to drive to a safer place off the motorway if you can, rather than stopping on the hard shoulder. Please also refer to our safety pages. Please also refer to our safety pages.
Drive Through
We have designed an electronic drive through of Active Traffic Management so you can familiarise yourself with the scheme - this can be accessed below.
This animation describes how Active Traffic Management works in practice.
More Information
For more information on Active Traffic Management please contact the Highways Agency Information Line on 08457 50 40 30 or email the ATM team at