Select Committee on Transport, Local Government and the Regions Ninth Report

The consequences of speed

Crashes and casualties


10. With a few exceptions, the evidence which we received argued that illegal and inappropriate speed had very serious consequences. The DTLR has stated that "speed is a major contributory factor in around one third of all road traffic accidents. This means that each year excessive and inappropriate speed helps to kill 1,200 people and to injure over 100,000 more".[13] There are other important factors: ie use of mobiles, drinking and driving, lack of sleep.

11. There was general agreement about why speed is such a danger. First, "at higher speeds there is less time to make adjustments for error, therefore a crash is more likely".[14] Professor Stradling of Napier University expressed the situation in the formula: Violation + Speed = Crash.[15] Detailed research by Gloucestershire County Council shows the relationship between speed and crashes.[16] In its survey, the reporting officer at a crash was required to indicate what went wrong (the 'precipitating factor') when there was an injury accident. In 97% of cases human error was to blame; in the others it was directly attributable to mechanical failure. When asked to identify other factors which had caused or contributed to the crash, officers attributed excess speed as a causation factor in 14% of crashes and inappropriate speed (such as loss of control) in a further 32%.

12. Secondly, in obedience to the laws of physics, speed makes crashes more severe. This is particularly important in cities, towns and villages, where pedestrians are particularly at risk. The Royal Society for the Prevention of Accidents informed us that:

"Hit by a car at 40 mph, nine out of ten pedestrians will be killed.

Hit by a car at 30 mph, about half of pedestrians will be killed.

Hit by a car at 20 mph, nine out of ten pedestrians will survive."[17]

In other words, as the DTLR notes: "The change from mainly survivable injuries to mainly fatal injuries takes place at speeds between 30 and 40 mph".[18] A considerable number of drivers are unaware of this. A survey undertaken for Brake found than one third of drivers thought that "the chances of a pedestrian dying if hit at 40 mph [was] 50% or less".[19]

13. We took oral evidence about the research which has been undertaken on the relationship between speed and crashes from experts from the Transport Research Laboratory, Professor Allsop of University College, London, Dr Carsten of Leeds University, the AA and the DTLR. The Transport Research Laboratory (TRL) summarised the evidence from national and international sources about the effects of speed on accidents, casualties and wider aspects of the quality of life.[20] The key findings of the research which TRL and others reported to us were that:

  • each one mph reduction in mean traffic speed is associated with a 5% reduction in accidents; the exact reduction depends on the type of road: thus: a 1 mph reduction in average speed would reduce accident frequency by:

- 6% on urban main roads and residential roads with low average speeds

- 4% on medium speed urban roads and lower speed rural main roads

- 3% on higher speed urban roads and rural single carriage way main roads.[21]

  • studies of individual drivers show that at a speed of 25% above the average speed, the risk of accident involvement rises more than 500%;
  • studies of roads show that the higher the average speed on a given type of road, the more accidents there are; and the bigger the spread of speeds, the more accidents;
  • 'before and after' studies show that measures to slow traffic have improved safety;
  • studies of cars involved in accidents show that they were travelling faster than the average speed of other cars on the same road.

14. The overwhelming majority of the memoranda we received agreed with these findings. Two, however, fundamentally disagreed. The RAC Foundation for Motoring and the Environment and the Association of British Drivers doubted whether speed made a significant contribution to crashes. The RAC Foundation pointed to a study by the West Midlands Police which found that less than 2% of traffic accidents were caused by excessive speed for the conditions.[22] The Association of British Drivers argued that "the only truly new research into accident causes is TRL323 and that "the worst abuses of statistics only claim that speed causes one third of accidents, with the true figure likely to be around 10 per cent.".[23] Part of the problem arises from a confusion of terms. The RAC Foundation and the Association of British Drivers claim that other organisations, including the DTLR, ACPO and the TRL, state that speed is a cause of 30% of road accidents; however, they do not argue this, but that speed is a contributory factor in about 30% of accidents. TRL Report 323, A new system for recording contributory factors in road accidents, which was published in 1998, set out the viability of requiring police officers to record contributory factors when visiting road accidents in addition to the data already collected. It noted that excessive speed was a definite factor in 6% of crashes. However, it should not be taken as evidence that speed is not a contributory factor. Sustrans stated:

"Although the much-quoted TRL Report 323 puts excessive speed as a definite factor in only six per cent of occasions a full list of instances given suggests that speed greatly contributes to the number and severity of almost all accidents and certainly more than the one third often asserted".[24]

Illegal and inappropriate speed is a major contributory factor in crashes and casualties in both urban and rural areas.

15. Several other witnesses argued that the effect of speed on road casualties was usually underestimated. The Traffic and Children Coalition, an alliance of charities, including many which work with children, claimed that the situation was almost certainly much worse than officially reported.[25] There is significant under-reporting of serious and slight injuries as many road traffic incidents are not reported to the police. The police sometimes mis-classify the severity of the injury and reporting rules ensure that anyone dying more than 30 days after a collision is classified as seriously injured.[26] A national study, TRL 272: National Hospital Study of Road Accident Casualties, found that:

 "Casualties recorded in the hospital survey were more severely injured than those recorded in police data, with around a quarter of casualties classified as seriously injured compared with 15% of casualties in Stats 19".

This is a huge difference. The BMA recommended that the health sector should adopt a primary role in the collection of high quality data on injuries and their consequences.[27] Speed may kill more and seriously injure many more people than has commonly been thought. The health service should play a more active part in the collection of data on injuries, and should be funded to do this.


16. The cost of road accidents is very high. The DTLR estimated that the "medical and ambulance costs attributed to road traffic accidents" was £540m in 2000.[28] The Institution of Civil Engineers pointed to a Government study in 1996 which had shown that the introduction of suitably engineered 20 mph zones on suitable urban roads could save over £2bn.[29] The Government's Tomorrow's roads - safer for everyone estimated the direct cost of road accidents involving deaths or injuries to be in the region of £3bn. a year.[30] In a subsequent study the DTLR estimated that

"the economic value of preventing injury crashes during 2000 would have been £12,170 m in 2000 prices and values. This figure includes lost output, medical and ambulance costs and human costs. When the total costs of police work, insurance and damage to property are added for all crashes...this figure swells to £16,959 m".[31]

The full cost to the nation of road traffic accidents is very large; a DTLR study has estimated it to be £17 bn in a single year. If drivers travelled at lower and more appropriate speeds, the savings to society would be immense, as the savings to individuals would be. If the measures recommended in this Report were to achieve a reduction of road traffic accidents by a third, the savings to society could be as great as £100 million per week.



17. The Road Accident statistics indicate casualties by road type, and indicate that most casualties occur on built-up roads.
Motorways Built-up roadsNon-built-up roads All speed limits
ksi *all ksiall ksiall ksi all
Pedestrians69(3)118(5) 9652(3588)43005(17591) 760(146)1763(375)10481(3737) 44886(17971)
Pedal cyclists3(0)10(0) 2790(821)20965(6562) 519(94)1948(368)3312(915) 22923(6930)
Car drivers & passengers1050


11996(908)9337(596)126743(9712) 11289(551)71735(5239) 21676(1215)210474(15859)
Two-wheeled vehicles110(0) 430(1)3716(54)17818(241) 2616(19)6362(69)6442(73) 24610(311)
All other vehicles243(3) 1575(21)1109(108)14494(1878) 992(28)6250(475)2344(139) 22319(2374)
All casualties1475(74) 14129(935)26604(5167)223025(35984) 16176(838)88058(6526) 44255(6079)325212(43445)
(* killed and seriously injured.)

(Source, Road Accidents Great Britain: 1998, DETR - taken from

New Directions in Speed Management, DETR, March 2000. The figures in brackets refer to the numbers of children)

In 1998 54% of road deaths occurred in rural areas, including both built-up and non-built-up roads. However, crashes in urban areas are more likely to kill or injure pedestrians. In 1998, 36% of those killed or seriously injured in urban areas were pedestrians.[32] As the table makes clear, motorways are the safest roads.


18. Whereas fewer drivers and passengers are killed on our roads than in most other European countries, pedestrians fare less well. British child pedestrian deaths and injuries are particularly high. More than 3,000 children were killed or seriously injured as pedestrians in 2000. The Institute for Public Policy Research concluded that "speed was a police recorded factor" in the death or serious injury of over 1,000 child pedestrians in 2000. "Each year around a fifth of all deaths of those aged 5 to 19 are due to road accidents".[33]

Child Pedestrian (aged 0-14) deaths per 100,000 population







Great Britain


Northern Ireland


United Kingdom
















Irish Republic














19. Poor people, and especially poor children, are disproportionately likely to be killed or injured as pedestrians. The Institute for Public Policy Research's memorandum provided preliminary results of its project which is looking at the links between child pedestrian accidents and social inequality. It shows that child pedestrian accident rates are far higher in more deprived areas. Children "in the 10 per cent most deprived wards... in England have an accident rate around four times that of the 10 per cent most affluent".[34] The pedestrian death rate for children from families in social class V is five times that for those from social class I.[35]

20. The reasons for these large inequalities are clear: speed is more common in less affluent areas and "children from more deprived backgrounds are going to experience the biggest impact on their quality of life as they are most likely to be trying to cross, play and live" near dangerous roads and are least likely to be in cars.[36] The Association of British Drivers pointed out that 80 per cent of pedestrian injuries result from pedestrians own actions. It suggested that the death of pedestrians may be caused by drug and alcohol abuse and that child pedestrian deaths may reflect the lack of supervision by parents.[37] On the other hand, the great bulk of memoranda very strongly rejected the idea that pedestrians and especially children and the elderly are to blame for their own deaths.[38] Most witnesses considered that it was unacceptable to have a situation where children died because they had to play on the streets, or elderly pedestrians because of a slight error of judgement. One witness explicitly contrasted the attitude shown in dealing with health and safety at work with that taken by highway engineers in dealing with road safety.[39]

21. Most deaths of car occupants take place on rural roads, but most crashes and pedestrian deaths in urban areas. Compared with several other European countries our child pedestrian death rate is high. Speed causes major health inequalities, especially in urban areas: child pedestrians who live in deprived areas are particularly at risk from road traffic.

The quality of life

22. Speed also has a huge impact on the quality of life through intimidation, severance and noise. The Slower Speeds Initiative argued that:

"Public space has been surrendered to traffic. The residual, disrupted and often derelict spaces left to pedestrians and cyclists indicate the low value placed on their safety and time".[40]

Professor Allsop observed that reducing speed could "help to return street space in towns and villages and the use of country lanes to people on foot, on bicycles and on horseback".[41] He considered that in many cases cost benefit analysis would show the advantages of constraining speed where it affects the quality of life.

23. Many cities are blighted by roads designed to maintain traffic flows. The Local Government Association argued that:

"The traffic free-flow philosophy as applied to town planning through the 1960s and 1970s has led to divided communities with the social implications which this brings...The former philosophy implied that the time savings of not allowing congestion to develop was more valuable to society as a whole than the disbenefit to the local community".[42]

Sustrans informed us:

"Highways [have] become roads for cars rather than streets for people ....Multiplied across a city, this impact can have devastating consequences. People will not visit, shop or live in an unattractive environment. Much of the urban decay and 'doughnut-effect' of city centres is caused by dangerous, speeding traffic. Those who can, leave".[43]

24. Not so long ago it was possible to enjoy a walk or ride down a country lane; now such a journey can be a nightmare. The Ramblers Association observed:

"Roads do not have footways. Pedestrians are therefore forced to walk within the carriageway and to share the space with motorised vehicles. Beyond the 30mph zones of a village, that traffic may well be travelling at the national speed limit and can take any form from an articulated lorry to a motorbike. Within living memory it would have been safe for walkers to move from the public rights of way network, along a linking stretch of carriageway, and back onto the rights of way network, but that is no longer the case".[44]

Riders are also severely affected by speeding traffic. The British Horse Society's most recent survey found that 99 per cent of respondents cited the speed of motor traffic as the biggest hazard faced by them when riding on the road. It was found that 5 per cent of the respondents had had an accident with a vehicle while riding in the preceding 12 months and 50 per cent reported a near miss. In Hertfordshire, there are an estimated 68,000 riders. Fewer than 3 per cent could go for a ride without using the roads at all.[45]

25. Speed is an important factor in noise levels. Tyre noise becomes a problem at higher speeds (over 30-40 mph for newer cars). The noise from traffic can spread for miles through the countryside. As the IHT notes noise increases as the square of the speed at higher speeds.[46] Formerly tranquil areas like the South Downs are now dominated by the sound of fast moving traffic on the A27 below. The situation is as bad in cities: a study in Huddersfield found that traffic noise interfered with the relaxation and sleeping of 20% of respondents.[47]

26. Many witnesses stressed that speed discourages people from walking and cycling.[48] The Health Development Agency pointed to research which shows that:

"the built environment, including road traffic density and speed, is a major influence on the quality of the experience of walking in urban environments...Increasingly, there is an acceptance that environmental considerations influence the level of physical activity".[49]

The TRL found that the speed of vehicular traffic was an important deterrent to cycling and, it was widely believed, walking.[50] It is hard to see how the Government will meet its target of trebling cycling by 2010 unless the speed of traffic is reduced on routes which cyclists use.

27. The Commission for Integrated Transport found that 20 mph zones had been "fundamental in prompting strong growth in walking and cycling".[51] While the precise relationship between traffic speed and walking is hazy,[52] there is little doubt that in cities where pedestrians have been given priority people walk and cycle more. The City of York Council has introduced "a danger reduction approach to speed management that has helped it meet national casualty reduction targets well in advance of target dates." This means that it has taken measures to slow traffic down. Such measures, together with the creation of a pedestrian and a cycle network, have also promoted walking and cycling: twice as many people in York walk to work as the national average and there has been an increase in cycling and a reduction of 28% in the number of cycling accidents.[53]

28. Speeding also indirectly affects health. Physical inactivity is a major public health problem in the UK. Health professionals, supported by a number of other witnesses, stressed that by discouraging walking and cycling speeding traffic led to inactivity, and hence the increased risk of illnesses such as coronary heart disease, colon cancer and diabetes. The Health Development Agency noted that:

"around 60% of men and 70% of women [fail] to reach the minimum recommendation of 30 minutes moderate activity at least five times a week...It is estimated that the population attributable risk of coronary heart disease from inactivity is 37%."[54]

The prospect of an unpleasant walk to the shops down a busy road with traffic travelling in excess of 30 mph makes most of us get into our car; a walk of the same distance in a pleasant and peaceful environment is an attractive proposition. The BMA pointed out that the:

"issue of children's exercise is crucial not only because of its link with their health and fitness in later life, but also because habits such as taking part in and enjoying physical activity are most easily acquired in childhood and may be difficult to acquire later".[55]

29. The threat posed by traffic has had a major effect on childhood. The relationship between traffic, air quality and health, including asthma, are well known. In addition, as the Traffic and Children Coalition stated:

"A major deterioration in children's quality of life has been the increasing loss of their independent mobility with many harmful consequences on their development, as highlighted in Mayer Hillman's classic 'One False Move' study".[56]

The memorandum quoted Mr Hillman:

"There appear to be alternative responses: either we can continue to with draw children from the growing threat that is posed, and inculcate fear in parents and children about the risks, or we can withdraw that threat from the children by 'taming' traffic."

30. There are serious indirect health effects of inappropriate traffic speed. Fast-moving traffic plays a part in discouraging physical activity by inhibiting walking and cycling in urban and rural areas. We recommend an increase in the number of dedicated cycle routes. Moreover, vehicles travelling at speed are noisy, sever communities and undermine urban regeneration.

31. Measures put in place to protect pedestrians from traffic travelling at speed such as railings, barriers and staggered crossings make matters worse and discourage walking. In its memorandum to this inquiry, the DTLR states

"Physical separation of traffic and pedestrians is appropriate in certain circumstances. For example barriers are erected on fast stretches of road to prevent pedestrians crossing at dangerous points."[57]

Unfortunately, barriers are not used in this limited way, but appear often to be a measure of first resort. In its inquiry into Walking in Towns and Cities, our predecessor Committee in the last Parliament concluded that barriers were employed to keep pedestrians off the road and to maintain traffic flows. It argued that if walking were to be encouraged there had to be a different approach to pedestrian safety based on danger reduction.[58] The Government replied that it would meet the Committee's objectives by issuing new policy guidance to local authorities which would "encourage them to develop the most pedestrian-friendly environment which can be achieved consistently with meeting the local casualty reduction targets and with properly serving the interests of other road users."[59] It is by no means certain that this will be adequate or that local authorities will make sufficient effort to humanise 'the traffic environment'. Pedestrian railings, barriers and staggered crossings are designed to maintain traffic flows and restrict pedestrian movement. They do not deal with the root of the problem which is that traffic is sometimes moving too quickly. The Government has failed to change this situation; it must advocate a policy which does not create urban areas where cars can speed and pedestrians are corralled behind barriers, but rather places where pedestrians can walk safely because traffic speeds have been reduced. The proposed guidance from Government on designing 'pedestrian-friendly environments' should reflect this policy.

13   Tomorrows roads, p. 48. Back

14   RTS 1 Back

15   RTS 45. Back

16   RTS 25; and see the AA (RTS 48). Back

17   RTS 16. Back

18   New Directions in Speed management, DETR, March 2000, p. 13. Back

19   RTS 50 Back

20   RTS 27 Back

21   The research is reported in TRL Report 421: M Taylor, D Lynam and A Baruya - Effects of drivers' speed on frequency of road accidents. Back

22   RTS 6. Back

23   RTS 11. Back

24   RTS 18. Back

25   The Traffic and Children Coalition is an alliance of charities, including the Child Accident Prevention Trust, the Child Poverty Action Group, the Children's Play Council, the National Children's Bureau, the National Family and Parenting Institute, the NSPCC and others (RTS 47). Back

26   RTS 47 Back

27   RTS 150 Back

28   Quoted by the Department of Health (RTS 151). Back

29   RTS 138. Back

30   Tomorrow's roads, p. 7. Back

31   The quotation in the PACTS memorandum (RTS 14) is from DTLR, Highways Economic Note 1, 2000, Valuation of the Benefits of Prevention of Road Accidents and Casualties; and see IHT (RTS 38). Back

32   New Directions in Speed Management, p. 11; and see PACTS (RTS 14). Back

33   RTS 51. Back

34   RTS 51. Back

35   Q 528. Back

36   RTS 153, and see RTS 51. Back

37   RTS 11. Back

38   Gloucestershire City Council told us: "The notion that pedestrians are largely to blame for pedestrian accidents is as much a cultural concept as a technical one" (RTS 25). Back

39   RTS 1. Back

40   RTS 34. Back

41   RTS 36. Back

42   RTS 21. Back

43   RTS 18. Back

44   RTS 10. Back

45   RTS 22. Back

46   RTS 38. Back

47   RTS 4. Back

48   Eg., the IHIE notes that lower speeds could improve the environment, quality of life and facilitate "more sustainable transport modes" (RTS 33). Back

49   RTS 153. Back

50   RTS 27. The National Cycling Forum has found that cycling in the UK has been in decline mostly because of a lack of safety. Reducing speed was one of the main areas for action (RTS 18). Back

51   Quoted by Sustrans (RTS 18). Back

52   TRL noted that "better knowledge is needed about the possible effect of traffic speed in suppressing walking activity." (RTS 27). Back

53   The information about York comes from the Health Development Agency (RTS 153). Back

54   RTS 153. Back

55   RTS 150. Back

56   RTS 47. Back

57   RTS 49. Back

58   Eleventh Report from the Environment, Transport and Regional Affairs Committee, 2000-01, Walking in Towns and Cities, HC 167-I. Back

59   Cm 5277. Back

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