Managed motorways

New technology can help make journey times more predictable.  Photo: © CPRE 

In January 2009 the Government announced £6 billion of spending on trunk roads, in order to create 520 additional lane miles across the country, of which two-thirds would be created through Hard Shoulder Running. 

By making better use of existing roads, Hard Shoulder Running is claimed to be good for the environment as almost no additional land is needed to increase capacity, other than for laybys every 800 metres that function as refugee areas. With so much proposed to be spent on this programme, we believe it is important to analyse costs and benefits of this and a wide range of alternatives carefully. 

Hard Shoulder Running is part of the 'managed motorways' programme, which actually covers a range of measures that aim to increase traffic capacity on dual carriageways as well as motorways. These measures include:

• Hard Shoulder Running (also known as Active Traffic Management): when there is congestion, signs on overhead gantries lower the speed limit and allow drivers to use the hard shoulder.  The cost of installing this is about a tenth of building an extra lane.
• Variable Mandatory Speed Limits (also known as Controlled Motorways): this is the same in that there are overhead gantries and lower speed limits during congestion, except that driving is not permitted on the hard shoulder.
• Ramp Metering: part-time traffic signals limit access from slip roads onto motorways to improve traffic flow.
• Intelligent Transport Systems: cameras and loops in the road surface monitor vehicle speeds and flows, enabling real time traffic information.  Information on disruptions is passed to drivers through roadside variable messaging displays, SatNav and the radio.

> Department for Transport roads policy

> Information about managed motorways  - Highways Agency

Stop-gap solution

Government policy concedes that traffic will grow by as much as 8-10% per year where new capacity is provided at congestion hotspots. Increasing capacity by whatever means is not a long term solution and the benefits are often gone within five years. Increasing capacity in fact simply tends to move traffic queues to surrounding roads, which are themselves struggling to cope. Not only does this mean a negligible improvement for most journeys, but also the increase in traffic on surrounding roads can reduce tranquillity in the surrounding countryside.

At a time when public finances are under pressure, transport schemes that actually have long term benefits, such as rail improvements, should be prioritised instead.  Small scale solutions like Intelligent Transport Solutions and Workplace Travel Plans can be a much more cost effective way of managing and reducing congestion.

> Tackling congestion through Influencing Travel Behaviour - Highways Agency

Counting carbon 

The Hard Shoulder Running pilot on the M42 around Birmingham has led to a 4% decrease in carbon emissions due to smoother traffic flows. With the decision to allow use of the hard shoulder at 60mph not 50mph, these benefits have gone.  Official figures show the managed motorway programme would increase total road transport carbon emissions by 0.4% compared to 0.5% for road widening, as both would generate new traffic. In other words it would cause 80% of the emissions that would be caused by a huge programme of road widening, which is now unaffordable anyway. That can hardly be said to be environmentally friendly.

Locking in benefits

The Government committed to trialling High Occupancy Vehicle (HOV) and toll lanes in 2004, as a way to lock in the benefits of increased road capacity. HOV lanes enable buses, coaches and people sharing cars and vans to bypass traffic queues and so encourage sustainable travel.

Yet six years later there is still only one HOV scheme implemented. The drop in traffic levels due to the recession provides an excellent opportunity introduce more HOV lanes on the outskirts of urban areas to lock in the benefits of reduced congestion.  Hard Shoulder Running schemes are designed to allow HOV lanes to retrofitted easily.

> High Occupancy Vehicle (HOV) lanes - Highways Agency

Visual intrusion 

The sign gantries needed every 800m on controlled and managed motorways can be very visually intrusive in sensitive landscapes. The Highways Agency says it may be able to change the spacing slightly to try to reduce the impact but due to the regularity of the gantries, this is likely to be of limited use. Lighting is needed along sections of road with hard shoulder running for safety reasons and this significantly increases light pollution.

On the continent many sections of motorway have speed limits below the national limit.  Introducing a 60mph limit on regularly congested sections of motorway in sensitive areas is a cost efficient and effective means of securing many of the benefits of controlled motorways without needing overhead gantries.  Limited Hard Shoulder Running close to congested towns and cities could be justified to increase modal shift and increase car occupancy rates.