Select Committee on Transport, Local Government and the Regions Appendices to the Minutes of Evidence

Memorandum by the Institution of Highways and Transportation (RTS 38)



  1.  Improving road safety is one of the cornerstones of the IHT. Reducing avoidable death and injury that excessive or inappropriate speed brings with it is fundamental. Consequently we welcome the Committee's Inquiry into this important issue.


Types of Speed

  2.  There are two things upon which we can all agree. Firstly, the faster you drive, the harder you crash. Secondly, speeding drivers kill and injure other road users in avoidable (or, at least, avoidably severe) accidents. But this does not only relate to excessive speed (exceeding the legal limit) but also, and often with more serious consequences, inappropriate speed (driving at a speed that is inappropriate for the prevailing circumstances, even though it may be within the legal limit). Accordingly, we believe the scope of the Inquiry should cover both excessive and inappropriate speed.

Types of Impact

  3.  Road traffic speed has social, economic and environmental impacts.


  4.  Each accident generates substantial costs in terms of resources, lost production, health care, social benefits and, of course, in personal pain, grief and suffering. The risks of accident, injury and death rise with speed, at all speeds. They rise faster as speed increases. The more severe the consequences being analysed (ie accident, injury or death), the faster risk rises with speed.1

  5.  But accidents and casualties should not be the only concern. There is a quality of life dimension too. High speeds create severance, fear, intimidation and perceptions of danger, particularly when different types of road users mix in close proximity. It is harder to quantify than accidents but nevertheless a factor that affects people's daily lives. In terms of research knowledge the Press Notice mentions the very high pedestrian casualty rate. This should also refer to cycle casualty rates too.


  6.  Road accidents have been estimated to cost the country over £16,000 million per year. But road traffic speed, or more accurately, faster journey times bring with them economic considerations and some benefits from time savings. We know that journey time falls with increasing speed, but falls more slowly as speed increases. Thus there are diminishing returns from increased speed in terms of journey times. Yet there are rapidly rising risks associated with increasing speed. Thus, there is a balance to be struck between the social and economic considerations and that balance should include the environmental considerations.


  7.  The environmental impacts per vehicle kilometre travelled depend on speed. Emissions of oxides of nitrogen, which contribute to acid rain, increase with speed, at all speeds.2 Emissions of particulates and carbon monoxide, which contribute to respiratory problems, increase with speed at higher speeds, but at lower speeds they decrease as speed increases.2

  8.  Catalytic converters have lower levels of emissions after the first few kilometres of travel from cold, but emissions of oxides of nitrogen and carbon monoxide still increase with speed at higher levels.

  9.  Emissions of carbon dioxide, which are proportional to fuel consumption and contribute to global warming, decrease as speed increases at lower levels but increase with speed at higher speeds (2).

  10.  Traffic noise (primarily engine and transmission noise) decreases as speed increases at lower speeds. However, noise increases roughly as the square of the speed at higher speeds (at which it consists mainly of tyre noise).

Urban and Rural Considerations

  11.  Road traffic speed raises different issues in urban and rural situations. We urge the Committee to take due account of the different issues and consequences in their Inquiry. Over the past decade, the proportion of total accidents and casualties in rural areas has increased, particularly the most serious accidents where speed is a major contributory factor. Furthermore, rural roads are expected to carry the brunt of future traffic growth. The Press Notice refers to the consequences of illegal and inappropriate speed for urban design. We urge that the Committee also considers the consequences for rural design where techniques to manage speed need to be sensitive to local civic and environmental conditions.

  12.  Special attention is required concerning roads between villages. In our Guidelines on Rural Safety Management (3) we argue for a whole route approach to speed and safety management. The primary aim is to ensure consistency of perception and design. The Guidelines also make recommendations concerning the development of a rural road hierarchy, which are referred to in the Secretary of State's report to Parliament on the subject, November 2001. The IHT is holding a major seminar on 12 February 2002 on Rural Road Speed Management and we do hope the Committee can be represented. In any event, we would be delighted to report back the key findings to the Committee in oral evidence.


  13.  This brief review of the major impacts arising from road traffic speed demonstrates that, broadly speaking, all the impacts except journey time argue against the highest speeds.


  14.  This section briefly outlines some important considerations that the Committee could usefully consider.

Public Acceptance

  15.  Choice of speed in the prevailing circumstances is a matter for the individual motorist. In a "free society" choice of speed is, rightly or wrongly, seen as an issue of personal freedom. It is an emotive topic. Thus it is important to present speed management policy effectively and demonstrate clear grounds for regulations and limits where selected.

  16.  However, as far as society's reaction to speed goes, it could be argued that perceptions are some 15 years behind the drink-drive issue. Something like 95 per cent of all drivers admit to exceeding speed limits. Thus the climate of public opinion, and perceptions of risks and impacts are important considerations.

  17.  There is evidence to suggest (4 and 5) that a large proportion of drivers and pedestrians think that speeds are generally too high. Most drivers see speed as a principle source of danger and recognise a range of advantages of speeds being lower. Thus the climate of public opinion may well be favourable to speed management policies, but more effort is needed to raise awareness of the risks and impacts, and change behaviour, to the extent seen in the drink-drive campaign. Affecting behaviour is the key to success.

Speed Management

  18.  Road design and classification are important. In short, speed limits need to match the function of the road and, broadly speaking, be seen by road users as being about right for the circumstances. Roads need to look as though motorists should drive along them at the appropriate speed. This should be an important aspect of any speed management hierarchy.

  19.  In the urban context there are useful lessons to cascade from the Gloucester Safer City project. In the rural context we strongly urge that a similar demonstration project be carried out to demonstrate the benefits of a whole route approach to rural safety management, the main elements of which are set out in our Guidelines (4).

Research Needs

  20.  There is a particular gap in knowledge and practice concerning speed management on high capacity routes.

  21.  There is no accepted measure of risk associated with pedestrians. There is no data on pedestrian accidents per distance walked.

  22.  There is little, if any, objective way of analysing accidents in rural villages as they are not identified in the data where there is no speed limit.


  23.  Enforcement is one of the so-called three "E"s of road safety—engineering, enforcement and education. As such it is an important component of speed management. However, as police resources are stretched, traffic enforcement is not as high a priority as some police forces might otherwise wish.

  24.  As far as speed is concerned, it is impossible to separate enforcement from the use of speed (or, more appropriately, safety) cameras. This area of speed management has come in for substantial criticism and there is undoubtedly room for better policy presentation. The public has not "bought-into" the policy or the technique partly based on the perception that the prime motivator is raising revenue and that cameras are deliberately inconspicuous. This is not the case, but perceptions count. We urge the Government to be resilient but to ensure that the policy is seen to be targeted at casualty reduction, perhaps, in certain circumstances, in association with additional vehicle actuated/responsive signs that advise motorists of their speed in advance of a safety camera. The safety camera is a valuable deterrent. Its use should be targeted and used flexibly to generate the greatest accident reductions. Reliable and cost-effective techniques to measure speed over whole routes, rather than at specific locations, should be developed and rolled-out more widely to tackle the tendency for drivers to step on the brakes when they see the camera ahead, and speed up again as soon as they have passed it.


  25.  Pedestrian railings were criticised in the Committee's Inquiry into Walking in Towns and Cities. Barriers and railings should not be a tool of first resort, but they do have an important role in appropriate circumstances, particularly on high speed roads or roads where the traffic environment can not be "humanised" to the extent that they become unnecessary.


  26.  We urge that there should be focused monitoring of road safety investment and outcomes in Local Transport Plans. In particular, if the Government's road safety targets are to be achieved, and road traffic speed is a contributory factor, the implication of the move to the Single Capital Pot for local authority capital investment will need to be monitored.


  27.  The Committee could usefully consider the penalties associated with driving and speeding offences to determine if they are appropriate and sufficient to act as a deterrent.


  28.  The Institution of Highways and Transportation (IHT) represents over 10,000 professionals working in highways and transportation in the public and private sectors. It promotes professional excellence as the leading learned society dealing with urban and regional transport systems and infrastructure at all stages of the project life cycle. We would be delighted to present oral evidence and answer questions if the Committee would find it of value.


  29.  The key documents dealing with speed and safety policy more generally are referenced in A Road Safety Good Practice Guide, DTLR, 2001, and will not be repeated here.


  30.  This submission draws on the following paper by Professor Richard Allsop OBE of University College London, a member of the IHT's Road Safety Panel:

  Allsop R E (1999), Understanding the impacts of speed, PACTS Conference, London, February 1999.

Carlton Roberts-James

Director of Technical Affairs


  1.  Andersson G and Nilsson G (1977), Speed Management in Sweden, Linköping; Swedish National Road and Transport Institute VTI.

  2.  Mitchell C G B (1993), Influencing speed and its environmental benefits—vehicle design. PACTS Conference, London, March, 1993.

  3.  Rural Safety Management (1999), IHT.

  4.  Kallberg V-P, Allsop R et al (1998). Recommendations for speed management strategies and policies. MASTER Deliverable D12.

  5.  Kallberg V-P, Allsop R et al (1998), Strategies and tools for speed management on European roads. European Transport Conference Loughborough, 1998.

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