Smart Motorway

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Very outdated - some road schemes that were done many years ago are still in the "Planned" section. Additionally, very basic information is given, in less detail than even the Wikipedia article!

Smart Motorways (formerly known as Active Traffic Management (ATM), Managed Motorways or Controlled Motorways) describes the modification of a motorway, usually in congested areas, with more advanced techniques to control and aid traffic flow. This either incorporates allowing traffic to drive on the hard shoulder under certain conditions (referred to as Dynamic Hard Shoulders or MM-DHS [1]) or converting the hard shoulder to a permanent traffic lane (referred to as All Lanes Running or MM-ALR). Originally referred to as Active Traffic Management, then Managed Motorways, latterly Highways England refer to these schemes as Smart Motorways.

On motorways upgraded to a Smart Motorway, more frequent overhead gantries or variable message displays are installed, emergency refuge areas (ERAs) are added to replace the loss of the hard shoulder, and variable speed limits are introduced. Signs and lights indicate if the hard shoulder is running and when to use it: sometimes the hard shoulder is used only for traffic heading off at the next junction, in other locations the hard shoulder might be converted to a running lane through the junction (known as Through Junction Running or TJR [2]).

History

The scheme is an expansion of existing schemes to use the motorway more effectively, such as Variable Speed Limits and Ramp Metering on motorways with variable traffic flows, where full widening might not be very cost-effective.

The first motorway to open with fully operating Active Traffic Management was the M42 between junctions 3A and 7. Plans to extend it to much of the English motorway network were announced by the Department for Transport in early 2009, and subsequently the scheme has been extended to the M6 and M40. It is an attractive political option because of its relatively low cost compared to full widening of motorways to D4M standard, which can cost more than £30m per mile widened. Concerns have been raised about the programme's safety implications as places to make emergency stops in the form of continuous hard shoulders are not available for much of the rush hour, as well as its longevity - the growth of traffic in the coming decades is likely to require more substantial widening or parallel construction at some point in the future.

Motorways being converted to Smart Motorways since 2013 will convert the hard shoulder to be a full-time running lane, as opposed to dynamic hard shoulders in previous schemes. Highways England explains this is to reduce confusion as to if the hard shoulder is open or not. [3]. The new design standards include using MS4 full-matrix variable message signs mounted at the verge more frequently than overhead gantries, however signals over each lane will be provided at on-slips and periodically on a long stretch of All Lane Running motorway. The distance between the emergency refuge areas (laybys) are also extended to up to 2.5km. [4]

How it works

On motorways converted to Smart Motorway, cameras and traffic loops are built into the motorway. When the traffic levels build up, the Highways Agency Regional Con­trol Cen­tres (RCCs) will first try and ease congestion by bringing in Variable Speed Limits. Sometimes this by itself may be enough to prevent the onset of congestion. If this doesn't work, Ramp Metering may also be switched on, if available.

If congestion is still building up, on schemes with a Dynamic Hard Shoulder, the RCC prepares to activate the hard shoulder as a traffic lane. Before doing so, a careful sweep is made to ensure the lane is clear of broken-down vehicles or other obstructions. If the Hard Shoulder is clear, overhead message boards and variable signs change to indicate the lane is open to all traffic. (If an obstruction is detected, the sequence is aborted). In some cases, the hard shoulder is purely for traffic exiting at the next junction; at other times, it becomes a normal lane of the motorway.

When the hard shoulder is closed, either a red X (without the flashing lights) or a blank overhead sign appears above the lane. [5]

In an emergency, the gantry or overhead message signs are used to show which lanes are closed and to move traffic away from obstructions.

Current Smart Motorways

Key: DHS: Dynamic Hard Shoulders, ALR: All Lanes Running, VSL: Variable Speed Limits, MTR: Ramp Metering, TJR: Through Junction Running

Image	Road	Junctions	Elements	Installed	Notes
	M1	6A - 10	VSL		Equipment already installed in 2008 widening.
	M1	10 - 13	DHS, VSL	Dec 2012	Currently A5-M1 link roadworks going on - the ATM systems are partially inactive during this stretch. Construction due to end around 2018-2020.
	M1	28 - 31	ALR, VSL	March 2016
	M1	31 - 32	VSL	March 2016
	M1	32 - 35A	ALR, VSL	J34 - 35A opened to traffic in December 2016, J32-34 is still under construction. Lane drop through J24.
	M1	39 - 42	ALR, VSL	December 2015
	M4	19 - 20	DHS, VSL	Spring 2014	In conjunction with M5 J15 - 17
	M5	15 - 17	DHS, VSL	Spring 2014	In conjunction with M4 J19 - 20
	M6	4 - 5	DHS, VSL, MTR, TJR (J4A west only)	November 2009
	M6	5 - 8	DHS, VSL, TJR	Spring 2013	Strengthening of the hard shoulder took place Between September 2009 and March 2010. Highways Agency Project
	M6	8 - 10A	DHS, VSL, MTR
	M6	10A - 11A	VSL	February 2016
	M6	11A - 13	ALR, VSL	February 2016
	M23	8 - 10	ALR, VSL	Summer 2020
	M23 Spur	9 - 9A	ALR (Airport-bound ONLY)	Winter 2019	fixed 50MPH speed limit
	M25	5 - 7	ALR, VSL	Spring 2014
	M25	23 - 27	ALR, VSL	November 2014
	M40	16 - (M42) 3A	VSL (Westbound only)	2009
	M42	3 - 3A	VSL (Eastbound only)	2009
	M42	3A - 7	DHS, VSL, MTR, TJR (J5 south only)	September 2006	The original trial instalation, publicly branded as "Active Traffic Management"
	M42	7 - 9	VSL	2009
	M62	25 - 26	ALR, VSL	September 2013
	M62	26 - 30	DHS, VSL	September 2013

Future planned deployment

Image	Road	Junctions	Elements	Expected Start	Expected Completion	Notes	Link
	M1	J32 - J35A		2010/2011	2011/2012		Highways Agency
	M3	J2 - J4A		November 2014	June 2017		Highways Agency
	M5	J4A - J6	ALR, VSL	January 2016	November 2016		Highways Agency
	M6	J13 - J19	DHS, VSL	After 2015		Strengthening of the hard shoulder took place Between September 2009 and March 2010	Highways Agency
	M25	J7 - J10
	M25	J23 - J27		Spring 2013	Autumn 2014
	M60	J8 - J18	VSL	July 2014	September 2017		Highways England
	M62	J18 - J20	ALR, VSL	July 2014	September 2017		Highways England
	M62	J25 - J30

The Highways Agency identified the following sections of motorway as having potential for future deployment of Smart Motorways - some sections have since been progressed to become schemes.

• Highways Angency Map from 2008
• Highways Agency map from 2013

Links

• The Highways Agency guide to Smart Motoways
• Roads.org.uk - Smart Motorways
• Legislation - The Motorways Traffic (England and Wales) (Amendment) (England) Regulations 2015 - Legislation allowing for provision of Emergency Refuge Areas
• BBC News: How smart are Highways England's smart motorways? (30.06.2019)