Motorways

This page provides an overview of Britain's motorways (with a focus on England's motorway network which is the bulk of motorways in Britain). It address issues relating to the safety and sustainability of Britain's motorways. 

Key facts about motorway crashes and casualties

  • In 2015, 6% of fatal crashes on Britain’s roads in 2015 occurred on the motorway.
  • 108 people were killed, an increase of 8% on the 2010-2014 average.
  • Serious injuries increased by 1% and have increased steadily since 2012. [1]  
  • Motorways have much lower crash rates per mile travelled than other road types (88 injury collisions per billion miles in 2014, compared with 819 on Britain’s urban roads. [2]
  • When they do happen, crashes on motorways are more than twice as likely to result in death compared with crashes on roads with lower speed limits. [3]

Key facts about motorway traffic volumes and emissions

  • Traffic on England’s strategic road network (trunk roads inclusive of motorways) grew by 19% between 2000 and 2015, with the biggest growth in light goods vehicles.
  • Traffic is expected to grow by up to a further 60% between 2010 and 2040. [4]
  • The SRN carries two thirds of England’s large goods vehicle (truck) traffic, largely run on diesel (which releases higher amounts of NOx than petrol). About a third of cars are also diesel. [5]

Who’s in charge of our motorways and what strategy are they following?

Most of Britain’s motorways, and motorway traffic, is in England. Motorways in England are part of the Strategic Road Network (SRN), meaning England’s motorway and all-purpose trunk roads (inclusive of dual carriageways and many single carriageway A roads).

The SRN is operated by Highways England. Highways England is a government-owned company established in 2015. (Previously, motorways were managed by a government agency called The Highways Agency.) Highways England is tasked with maintaining, running and extending this network and its funds are provided by central government’s Road Investment Strategy (RIS) [6].

The current RIS is for five years (2015-2020). This strategy is funding development of the SRN. Out of a total fund of more than £15bn, the majority is for “major improvements”, and “maintenance and renewals”. The proportionally small remainder is ring-fenced for measures including a relatively small £70m for safety improvements.

Highways England has produced a road safety strategy [7] and a strategy for investment in innovation [8] on its network. Highways England’s performance is monitored by the Office of Rail and Road (ORR).  

In Scotland, Wales and Northern Ireland, responsibility for motorways is devolved to those governments.

Identifying and improving the star safety ratings of England’s motorways

Part of Highways England’s safety strategy is to improve the safety ratings of its motorways. It is developing its own road safety assessment rating system for the Strategic Road Network; this will be a tailored version of the international iRAP system [9] considering incident location, collision data, traffic volume, and vehicle speed and road layouts, and “starring” roads on a scale of one to five, with five being the highest safety standard.

The rating system will be applied to the SRN and inform ongoing programmes of works, to reach a Highways England target of 90% of travel on the SRN being on roads with a safety rating equivalent to EuroRAP three star (the European version of iRAP) by the end of 2020 [10]. The rating system is aimed to be developed and applied to the network in 2018, to inform route strategies and investment programmes moving beyond that date.

A rating of the SRN in 2010 placed 50% of the motorway network at 3 star and 50% at 4 star. Highways England is spending its ring fenced safety funds on: “retrofitting measures to improve the existing road network” inclusive of central barriers. Many of the improvements however will be urgent remedial work to raise star ratings on two star A roads.  

SMART Motorways

To alleviate congestion, SMART motorways [11] are aiming to deliver more than 4,000 miles of extra capacity. SMART motorways use active traffic management techniques. These monitor traffic flow and aim to achieve improvements in traffic flow by varying speed limits and allowing hard shoulder (or ‘all-lane’) running (to increase available space). SMART motorways can also activate warning signs alerting drivers to hazards / congestion ahead and close lanes (for example if there has been a crash or breakdown).

Initial results following implementation of all-lane running SMART motorways on sections of the M25 indicate no change in safety [11]. However, many people have voiced concerns about ‘all-Lane Running’. Parliament’s Transport Select Committee concluded benefits could be outweighed by costs to health and safety [12].

Lower crash rates on motorways

Motorways are well known for having much lower crash rates per mile travelled than other road types. In 2014, there were 88 injury collisions per billion miles on British motorways, compared with 340 on rural British roads and 819 injury collisions per billion miles on urban British roads. [2]

This is for multiple reasons. However, design of motorways, and type of road user allowed on them, are likely to contribute significantly to the lower crash rate. Motorways:

  • are a simpler road system than many other roads. For example, vehicles travelling in opposing directions is separated, and entrances/exits predictable;
  • exclude people on foot, bicycle and other non-motorised forms of transport.

Higher death rates on motorways

When crashes do occur, the likelihood of death is higher on motorways than on other roads. Crashes on 70mph (113km/h) roads are more than twice as likely to result in death as crashes on roads with lower speed limits.[3] Again, this is for multiple reasons, but is likely to be contributed to significantly by:

  • higher allowable speeds compared with other roads, meaning it takes longer to stop;
  • greater proportions of heavier, larger vehicles than other roads;
  • large amounts of traffic all travelling at speed.

Casualty reduction targets

Highways England has set itself targets for casualty reduction. Its ultimate aim, as stated in its five year Health and Safety Plan [13], is that “no-one should be harmed when travelling or working on the strategic road network”, with a goal of achieving this by 2040. It has a target of a 40% reduction in people killed and seriously injured (KSI) on the network by 2020 against the 2005-9 average base line.

The British government’s Road Investment Strategy also states: “By 2040 we aspire to a network in which the number of people killed or seriously injured on the SRN will be approaching zero.” [6]

Investigations into causes of deaths on England’s SRN

A 2014 Highways England-commissioned study [14] of fatal collisions on the Strategic Road Network (including motorways) by TRL (the UK’s Transport Research Laboratory) studied 159 out of 192 fatal collisions and found:

  • More than half fatal collisions (90) were caused by multiple factors relating to a) human behaviour (particularly bad driving and speeding), b) the road and its environment (eg inadequate barrier, bad weather) and/or c) the vehicle (tyres, brakes, etc).
  • Although nearly all crashes had a human element, countermeasures influencing behaviour of people could have prevented only 4% of the collisions: the rest required countermeasures relating to the road and its environment and/or the vehicle.

The research suggested counter measures that could have prevented this cohort of crashes, including Advanced Driver Assistance Systems (ADAS) fitted to vehicles (notably automated emergency braking and intelligence speed assistance) and improvements to the road (such as better barriers).

TRL estimated how many deaths in these fatal crashes would have been prevented if certain ADAS systems had been regulated. TRL concluded more than a third (34%) of deaths studied could have been prevented if AEBS had been mandated on all vehicles (currently it's only mandated on trucks and coaches), and one in seven (14%) could have been prevented if advisory ISA had been mandated. Read more about  ADAS

This report demonstrates the importance of a safe system approach on the SRN, through improvements to the road environment and vehicles using the network, to mitigate human error. 

Pollution caused by traffic on England’s motorways

Britain’s ultra-low emission vehicle strategy [15] wants “every new car to be an ULEV from 2040 and an effectively decarbonised fleet by 2050.” For the first time, in 2016, more than 1% of new vehicles registered were ULEV.

Motorways represent only a small fraction of the entire road network in terms of length, they account for a substantial proportion of total road traffic and therefore emissions. Without very rapid growth in ULEV cars towards the government’s strategy, however, use of the strategic road network (inclusive of England’s motorways) is expected to increasingly contribute to levels of climate changing and lung-damaging pollutants due to rising traffic volumes, particularly bearing in mind the significant proportion of commercial vehicle traffic on our motorways:

  • traffic overall grew by 19% between 2000 and 2015, with the biggest growth in light vehicles;
  • miles travelled by vehicles on the SRN rose from under 85bn in 2012/13 to nearly 90bn in 2015/16;
  • traffic is expected to grow by up to a further 60% between 2010 and 2040. [16]
  • The SRN carries two thirds of England’s large goods vehicle (truck) traffic, largely run on diesel (which releases higher amounts of NOx than petrol). About a third of cars are also diesel. [5]

ORR, in its Annual Assessment of Highways England’s performance, says: “Traffic growth presents specific challenges for the company in almost all of its outcome areas. For example ….it must manage the impact of traffic growth on safety, network condition and air quality.” [17]

Lack of targets to combat pollution

The thresholds for NOx pollution are set out in the EU Directive on Ambient Air Quality (2008/50/EC) and the Air Quality (England) (Amendment) Regulations (2002) and supporting Air Quality Strategy, targeted at improving areas of poor air quality.

Despite the urgency of climate change, the burden on the NHS due to respiratory disease, and the contribution of traffic, Highways England has no target for reducing emissions of carbon dioxide, NOx nor particulates from use of its roads.

Highways England has identified in its Operational Metrics Manual [18] that there is a risk to the company delivering better environmental outcomes due to: “lack of formal legislation for Highways England to deliver and enforce any air quality intervention measure either on the Strategic Road Network (SRN) and / or local road network. There is no clear mandate, against a backdrop of an open network, to implement specific interventions on the SRN eg Low Emissions Zone (LEZ), which may hamper our ability to help improve air quality. Highways England are aware that in principle a Local Authority may declare an LEZ on their road network, but it is unclear as to whether they have any jurisdiction over traffic using the SRN.”

In its manual, Highways England also identifies the link between greater usage and pollution: “An increase in traffic would lead to worsening in air quality in areas of poor air quality alongside the SRN.”

Highways England is carrying out ten air quality pilot studies, completed over three years ending in 2017 to look at air quality "exceedences and the range of concentrations in a given area" . It says "this is supported by work to understand the reasons for the problem eg detailed traffic numbers and fleet compositions. A pilot study may be targeted at specific interventions and not all studies will be identical. The anticipated outcomes will guide potential targeted mitigation solutions.”

Speed limits and speeding on motorways

British motorways have a speed limit of 70mph. Some vehicles on motorways have a speed limit of 60mph, inclusive of articulated trucks, coaches longer than 12m, and vehicles that are towing trailers or caravans. [19] Speed limits can be lowered temporarily for safety reasons (for example roadworks), and communicated to drivers through visual displays.

While vehicles vary in their braking ability, a car travelling at 70mph has a total stopping distance, in dry conditions, of about 96m, or 24 car lengths. This is greater in wet and icy conditions. If braking is carried out by the driver (rather than an automated emergency braking system) the car will travel about 21 metres in less than a second before the driver can even hit the brakes.

A survey by Brake and Direct Line found six in 10 (60%) UK drivers admit breaking 70mph motorway speed limits by 10mph or more, and a similar proportion (57%) sometimes leave less than the recommended two-second gap between themselves and the vehicle in front, making it impossible to stop in time in an emergency [20].

Any increase in speed makes a difference to stopping distances and crash likelihood. At 80mph (129km/h), stopping distances are 27% greater than at 70mph (about 122 metres compared to 96 metres). Read facts on stopping distances.

It has been proposed in the past (and then shelved) to raise the UK motorway speed limit to 80mph. Research predicted it would cause 25 more deaths and 100 more serious injuries annually if the UK motorway speed limit was raised [21]. Parliament's Transport Select Committee estimated it would result in a 10% rise in casualties on motorways [22].

Higher speeds on motorways also lead to increased fuel consumption and carbon emissions. Vehicles travelling at 80mph use 10-20% more fuel than those travelling at 70mph, and it's been predicted that a rise in the limit to 80mph would mean an additional 2.2million tonnes of carbon entering the atmosphere each year [23]. It has also been found that 80mph limits would be unlikely to provide a significant improvement in journey times, especially on a congested network. An increased speed limit for cars would mean bigger differences between them and the maximum speed of trucks and coaches, contributing to ‘bunching’ and unnecessary congestion. A report by the Road Safety Foundation found the motorway network is 'unfit' for 80mph limits [24].

End notes

[1] Reported Road Casualties Great Britain 2015, Department for Transport, 2016
[2] Understanding the strengths and weaknesses of Britain’s road safety performance, TRL, 2016
[3] New Directions in Speed Management: A Review of Policy, Department for Transport, 2000
[4] Annual Assessment of Highways England’s Performance April 2015- Mar 2016, ORR
[5] Vehicle Licensing Statistics 2014, Department for Transport,

[6] Department for Transport, Road Investment Strategy 2015-2020
[7] National Incident and Casualty Reduction Plan, Highways England, 2016
[8] Innovation, Technology and Research Strategy, Highways England, 2016
[9] irap.net
[10] National Incident and Casualty Reduction Plan, Highways England, 2016
[11]
Smart motorways programme, Highways England, 2016
[12]
All-Lane Running: report, Transport Select Committee, 2016
[13] Highways England, Health and Safety five year plan, 2015
[14] Towards Zero, TRL, McCarthy and Barrow, May 2016
[15] Department for Transport, Driving the Future Today A strategy for ultra low emission vehicles in the UK, 2013
[16] [17] Annual Assessment of Highways England’s Performance April 2015- Mar 2016, ORR
[18] Highways England, Operational Metrics Manual, 2016
[19]
Speed Limits, Department for Transport, 2016
[20]
Motorway driving, Brake and Direct Line, 2014
[21]
Speed Limits: a review of evidence, RAC Foundation, 2012
[22] Road Traffic Speed: report, Transport, local government and the regions select committee, 2002
[23]
Third Progress Report to Parliament, Committee on Climate Change, 2011
[24] Unfit for 80, Road Safety Foundation, 2012

Last updated October 2016