New Directions in Speed Management · New Directions in Speed Management – A Review of Policy 8...

New Directions inSpeed Management

– A Review of Policy

New Directions in

Speed Management

A Review of Policy

March 2000

Department of the Environment, Transport and the Regions: London

Department of the Environment, Transport and the RegionsEland HouseBressenden PlaceLondon SW1E 5DUTelephone 020 7944 3000Internet service http://www.detr.gov.uk

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CONTENTS

FOREWORD 5

CHAPTER ONE

Introduction 7

Origins of the Review 7Policy background 7The Review and Report 9

CHAPTER TWO

Findings 10

The effects of speed on road safety 10Vehicle speeds and the environment 13The effect on quality of life 15Health 15The economy 16What people say and what they do 16Deciding what speeds are right 17Current measures for influencing vehicle speeds 18

CHAPTER THREE

Analysis 21

The effects of vehicle speeds 21Urban speed management 22Rural areas 24Motorways and dual carriageways 26Achieving appropriate vehicle speeds 27

CHAPTER FOUR

Recommendations 31

Overview 31Action plan 31

CHAPTER FIVE

References 36

TECHNICAL ANNEX

Foreword

REVIEW OF SPEED POLICY

As the Head of the Road Safety and EnvironmentDirectorate, I am very pleased to enclose the reportof the Review of Speed Policy.

In its White Paper on the Future of Transport, theGovernment said that in the interests of achievingour road safety targets it would develop a speedpolicy that would take account of the contributionof reduced speeds to environmental and socialobjectives as well as to road safety.

You launched the review in October 1998. Sincethen I have had responsibility for ensuring that thereview reaches a successful conclusion.

To this end, we have consulted representatives ofenvironmental interests, motorists, localauthorities, the police, academics and many othersto reach an informed view of the issues.

Our road safety record is one of the best in theworld but we can do better, particularly for themost vulnerable road users and especially children.

Vehicles speed is perhaps the most importantcontributor to road casualties so we need to tacklethis issue if we are to achieve our targets.

We have looked closely at the precise nature of theproblem on the different road types to establishwhether change was required in the speed limit, theactual speeds driven, or both.

We have examined how we could develop bestpractice in engineering, enforcement, educationand publicity to achieve a workable and cost-effective approach.

The review has taken us a long way forward.We believe that a national framework fordetermining appropriate vehicle speeds is needed,but we also have to deepen our understanding ofthe affects of speed on the environment and thetrade offs with the economy.

Our aim should be for appropriate speeds on allroads. Speed limits to manage vehicle speeds willneed to be rational, consistent, readily understoodand appropriate for the circumstances. Such limitsshould help gain both compliance and even lowerspeeds where conditions dictate. Together thesewill make an important contribution to thereduction in death and injury on our roads.

I believe the recommendations in the reportprovide a sound framework for the future and I commend it to you and your ministerialcolleagues.

Yours sincerely,

John PlowmanRoad Safety and Environment

5

Foreword

CHAPTER 1

Introduction

Origins of the Review1. When the Government published the White Paper A New Deal for Transport: Better for Everyone it decided to set in hand a review of speed management. There was a widespread view that people were driving cars and other motor vehicles too fast. Many people thought speed limits should be lowered and that lowerlimits would automatically improve safety and bring environmental benefits. Others thought thatlimits were not observed because they were too low. So this review was:

“to develop a speed policy that takes accountof the contribution of reduced speeds toenvironmental and social objectives as wellas to road safety.”

2. Policies were to be practical and cost effectivebecause damaging the economy would not meetwider social objectives.

3. We have consulted many people withvaluable views and advice about speed issues. Wehave met groups of representatives ofenvironmental interests, motorists, local authoritiesand the police. We issued a discussion document inAugust and held a conference on 15 September lastyear attended by 300 people. While we wereundertaking the review, the Scottish Executive andthe National Assembly for Wales were created andtheir staff have taken part. Although nationalspeed limits are a Great Britain responsibility, localones are very much a matter for the Executive andthe Assembly in Scotland and Wales.

Policy background4. The wider policy background is important.

ROAD SAFETY STRATEGY

5. We had already announced proposals for aroad safety strategy for the next decade withcasualty reduction targets. The strategy will includethe Government’s response to the principalconclusions of this speed review. Ministersparticularly want these policies to address childroad safety.

CLIMATE CHANGE

6. The UK has taken on challenging targets forreducing its greenhouse gas emissions. Under theKyoto Protocol, it has a legally binding target toreduce emissions of a basket of greenhouse gasses to 12.5% below 1990 levels by 2008-2012. It alsohas a domestic goal to reduce emissions of carbondioxide, the most important greenhouse gas, by20% below 1990 levels by 2010. Changes to speedpolicy could have positive or negative effects onour ability to meet climate change targets.

AIR POLLUTION

7. Road transport is one of the major sources of local air pollution. It also accounts for two-thirdsof all emissions of four of the eight pollutants forwhich the national air quality strategy setsreduction targets. One suggestion for improving air quality in urban areas is to introduce suitabletraffic management schemes. We need to considerwhat is suitable.

7

Introduction

New Directions in Speed Management – A Review of Policy

8

HEALTH

8. The White Paper Saving Lives: Our HealthierNation sets targets for reducing deaths and seriousinjuries from all accidents. There is also referenceto reducing road casualties in the Scottish WhitePaper Towards a Healthier Scotland.

9. Cutting traffic speeds could also help achieveother health objectives. Reducing coronary heartdisease and stroke is another priority in OurHealthier Nation. The Department of Healthrecommends people take more exercise, such asmore walking and cycling “in a safe environment.”

10. An improvement in air quality would reducerespiratory disease and lessen its effects.

11. Targeted measures to moderate vehicle speedscan encourage more cycling and walking by makingthem safer and more attractive. Surveys showclearly that fears of traffic danger, and speed inparticular, lead more parents to take their childrento school by car (see for example Hillman et al1991). This is turn contributes to the peak hourtraffic levels.

REGENERATION

12. Thriving town centres are the focus of urbanlife. People want well-planned, attractive towncentres where they can live and work and enjoyshopping and the local culture. Speed managementcan contribute to a safer, more pleasantenvironment and to a wider choice of transport.Traffic calming measures that are sympathetic totheir surroundings can, for instance, encouragewalking and cycling. Traffic management can beengineered to improve reliability for bus journeys.

13. Speed management in rural areas can helpprevent communities being cut in two by frequentfast traffic through villages.

THE ECONOMY

14. There are wider economic implications too.There are real benefits to industry, business,

commuters and other motorists of being able toreach their destinations reasonably quickly.

15. Reliable journey times are also important forlorry and bus movements because they are afoundation of many modern industries, and aretaken into account when investment is planned.

16. Reducing speeds in congested conditions canbe helpful, of course, but unnecessary suppression ofspeed could be damaging.

GENUINE CAR DEPENDENCE

17. Speed management policy may particularlyaffect people who rely on car transport in theabsence of any realistic alternative. Motor vehiclesare essential to many people, especially those withmobility impairments or who live in rural areas.Their needs must be recognised.

OBJECTIVES

18. These are the objectives that speedmanagement policy sets out to meet. Clearly someof these are not compatible. Speed policy involvesdifficult decisions on trade-offs between benefitsand disadvantages and must resolve conflictsbetween objectives to strike the right balance.

19. This document does not contain all the finalanswers. We expected to find areas where theavailable information was not good enough for usto be confident about every detail, and we havefound some. We need better tools for judging costeffectiveness of some measures.

20. There will be more work – and moreconsultation – to develop policies in detail. Weneed to be aware of future changes, for example invehicle performance, which might provide betterways of achieving objectives. But we do knowenough to set the directions in which policy mightgo and to recommend action now where the reviewreveals flaws in what we are doing.

Introduction

9

The Review and Report21. The review was launched on 23 October 1998by Lord Whitty. It was divided into three stages.The first stage was to identify the main policy issuesthrough consultation within DETR and othergovernment departments. We also began to exploreexisting research on traffic speed and its effects, andto undertake an analysis of current practice andlegislation, both here and abroad. We will publishthe full literature review later this year.

22. The second stage was for wider consultationon the impact of speed and the effectiveness ofcurrent policies. We issued a discussion paper on 10 August which set out current policies andevidence from research. We had more than 100 responses.

23. The third stage of the review involvedanalysing the results of both the consultation andthe literature review to prepare recommendationsand conclusions.

24. This report sets out the findings of the reviewof speed policy. It makes recommendations forfuture polices, and areas where further informationis needed to help develop new initiatives.

25. Research referred to in the report is listed onpages 36 to 38 alphabetically by source.

26. The terms used in this paper are set out in thetechnical annex.

CHAPTER 2

Findings

The effects of speed onroad safety

WHERE AND WHEN CASUALTIES OCCUR

27. The table below shows the number of peoplekilled and injured by type of road in 1998. It showstotals for killed and seriously injured (ksi) and forall casualties. The figures in brackets show thenumber of children up to the age of 15 years ineach category.

10


Motorways Built-up Non-built-up All speed roads roads limits

ksi all ksi all ksi all ksi all

Pedestrians 69 118 9652 43005 760 1763 10481 44886(3) (5) (3588) (17591) (146) (375) (3737) (17971)

Pedal cyclists 3 10 2790 20965 519 1948 3312 22923(0) (0) (821) (6562) (94) (368) (915) (6930)

Car drivers & 1050 11996 9337 126743 11289 71735 21676 210474passengers (68) (908) (596) (9712) (551) (5239) (1215) (15859)

Two-wheeled 110 430 3716 17818 2616 6362 6442 24610vehicles (0) (1) (54) (241) (19) (69) (73) (311)

All other vehicles 243 1575 1109 14494 992 6250 2344 22319(3) (21) (108) (1878) (28) (475) (139) (2374)

All casualties 1475 14129 26604 223025 16176 88058 44255 325212(74) (935) (5167) (35984) (838) (6526) (6079) (43445)

(Source, DETR 1999a)

Findings

11

PEDESTRIANS AND CYCLISTS

• In urban areas, injuries to pedestrians wereabout 20% of total casualties but 36% of thekilled or seriously injured.

• Of all killed or seriously injured children(15 years and younger), 61% are injured aspedestrians. Children make up 37% of allpedestrian casualties and 41% of those in urbanareas.

• Injuries to pedal cyclists were 7% of allcasualties and 7.5% of the killed or seriouslyinjured. Of these 31% and 29% respectivelywere children.

DRIVERS AND PASSENGERS

• The largest proportion of injuries on built-uproads are sustained by car drivers and passengerswho make up 57% the total, about 35% themkilled or seriously injured.

• Most road deaths (54%) occur in rural areas. By far the largest group (65%) are car driversand passengers.

• Of all car occupant deaths, about 70% occur on rural roads and this is the largest singlegroup of deaths on any category of road.

• The motorway network sees about 4% of totalinjuries, 3% of the killed or seriously injuredand 5% of fatal casualties.

CASUALTY RATES

28. If we take into account the distance travelledby different transport methods, riders of bicyclesand two-wheeled motor vehicles are about equallylikely to be injured. The rate is about 580 casualtiesfor every 100 million vehicle kilometres. But a riderof a two-wheeled motor vehicle is nearly twice aslikely to be killed or seriously injured as a cyclist.

29. The rates for car drivers are 36 casualties per100 million vehicle kilometres and 3.7 killed orseriously injured casualties (DETR 1999a).

30. There are some doubts about the quality ofthe data on distance travelled.

31. A study of walking patterns in Northamptonin 1994 indicates that the risk to pedestrians isabout 400 casualties per 100 million kilometreswalked and just over 60 casualties per 100 millionroads crossed (Ward et al 1994).

32. The rates commonly used for pedestrians aremeasured in casualties per 100,000 people. Theseare 78 pedestrian casualties per 100,000 populationor 18 killed or seriously injured. Measured this way,the rates for cyclists are 40 and 5.8 respectively.

TIME OF DAY AND COLLISIONS

33. Between the hours of 1900 and 0700 about15% of the total vehicle kilometres are travelled.During this same period about 30% of injuryaccidents are reported. So the average risk of anaccident per kilometre travelled between 1900 and0700 is double that for the period 0700 to 1900.The likelihood of being involved in an accident inthe evening is far greater for the 16 to 25 age groupthan for any other age group (Thorburn Colquhounfor DETR, to be published)

SPEED AND THE RISK OF COLLISION

34. The relationship between speed and safety isa complex one. But from the national andinternational literature there is overwhelmingevidence that lower speeds result in fewer collisionsof lesser severity (Finch et al 1994, Taylor et al2000, Transportation Research Board 1998). Someinteresting conclusions can be drawn from researchso far.

35. In any given situation, the faster the averagetraffic speed, the more collisions there are.

• Accident frequency rises disproportionatelywith increasing speed. It rises approximatelywith the square of the average traffic speed(providing the ratio of the standard deviationto the mean remains constant). For example,on urban roads a 21% increase in collisionscould result from a 10% increase in meanspeeds (Taylor et al 2000).


12

• Speeding or inappropriate speed contributes toa significant percentage of all crashes and ahigher percentage of more serious crashes.Driver error is a contributory cause in over 90%of accidents: driving too fast is a driver error injudging what is safe.

• About a fifth of rural accidents involve vehiclesgoing too fast for the situation with a furtherquarter likely to be associated with speed(Sabey 1993).

• In an urban area about 4% were directly relatedto excessive speed and another 21% due tospeed related factors (Carsten et al 1989).

36. Broughton et al’s (1998) work indicates thatexcessive speed was a contributory factor in 424 ofthe 2795 accidents studied (about 15%). But this islikely to be an underestimate. Speed will have beena part of the reason for other factors such as failure

to judge another person’s path or speed, whichcaused 623 of the accidents, about 22%. It is notpossible to quantify these contributions directly.

37. New research (Taylor et al 2000) hasexamined the scope for reducing collisions throughspeed management. Broadly each 1 mph reductionin average speed is expected to cut accidentfrequency by 5%. This is a robust general rule, butnow we have a much fuller picture which indicatesthat the reduction varies according to road type asfollows:

• about 6% for urban main roads and residentialroads with low average speeds;

• about 4% for medium speed urban roads andlower speed rural main roads; and

• about 3% for the higher speed urban roads andrural single carriageway main roads.

0%

1%

2%

3%

4%

5%

6%

7%

8%

15 20 25 30 35 40 45 50 55Mean speed (miles/h)

Per

cent

red

uctio

n in

acc

iden

t fre

quen

cy

UrbanRural

'5% per 1mile/h'

(source: Taylor et al 2000)

Findings

13

38. The greatest reduction in casualties wouldcome from reducing the speeds of the faster drivers(Taylor et al 2000, see annex):

• if the proportion of speeders doubles, accidentsgo up by 10%;

• if their average speed goes up by 1mph, if allelse is held constant accidents go up by 19%;and

• if an individual drives more than 10-15% abovethe average speed of the traffic around them,they are much more likely to be involved in anaccident (Maycock et al 1998, Quimby et al1999a and b – see annex).

39. From surveys of 800 English car driversStradling et al (1999) find that one in three ofthose drivers who had been penalised for speedingoffences in the last three years had been involvedin an accident as a driver in the same period.

40. Research also indicates that drivers scoringhigh as ‘violators’ on the Manchester driverbehaviour questionnaire (see annex) are likely tospeed and ‘violate’ other road traffic rules such asclose following, red-light running, getting angrywith other drivers, and drinking and driving.Stradling also proposes that ‘violations’ reducesafety margins so that there is less room or time tocorrect errors such that:

Violation+Error=Crash (Stradling 1999)

SPEED AND INJURY SEVERITY

41. The likelihood of being seriously injured in acollision rises significantly with small changes inimpact speed. The impact speeds at which thisincrease is most pronounced are lower than mostwould think. The probability of serious injury to abelted car occupant in a front seat at an impactspeed of 30mph is three times greater than at20mph. At 40mph it is over five times greater(Hobbs and Mills 1984), see annex.

42. For pedestrians and cyclists the reality is evenmore stark. At-the-scene investigations of collisionsinvolving pedestrians and cars or car-derived vansfound that 85% of fatalities occurred at impactspeeds below 40 mph (Ashton and Mackay 1979).This compared with 45% which occurred at lessthan 30 mph and 5% at speeds below 20 mph.

43. About 40% of pedestrians who are struck atspeeds below 20 mph sustain non-minor injuries.This rises to 90% at speeds up to 30 mph, seeannex. The change from mainly survivable injuriesto mainly fatal injuries takes place at speeds ofbetween about 30 and 40 mph (Ashton 1981).Elderly pedestrians are more likely to sustain non-minor injuries than younger people in the sameimpact conditions.

44. It is the combination of speed and lack ofprotection that makes motorcyclists vulnerable.

Vehicle speeds andthe environment45. There are direct relationships betweenvehicle emissions and speed. These relationshipsdiffer depending on the emission in question.

GREENHOUSE GASES

46. Carbon dioxide (CO2) emissions areproportional to fuel consumption. At lowerconstant speeds total emissions of CO2 arerelatively high. With increasing speed theseemissions decrease until a threshold of about 30 mph(50 km/h). Above this any increase in speed leadsto a steep increase in CO2 emissions. Driving stylewill also have an impact on this relationship. Hardacceleration increases emissions, and engine tuningis also a factor.


14

AIR POLLUTANTS

47. Production of oxides of nitrogen (NOX)follows a different pattern from carbon monoxideor hydrocarbons. Emissions of NOX go up as avehicle’s speed increases, with the greatest rate ofincrease occurring at higher speeds. So reductionsin speed generally lead to reductions in NOX. Theeffect is less important in urban areas as muchhigher speeds are unusual. Engine temperature andload are also relevant. For example, a car towing acaravan up a hill at 30 mph would be likely to emitmore NOX than the same car without the caravanon a motorway at 70 mph.

Figure A9: CO2 emissions from a Euro II petrol car relative to vehicle speed

Figure A9: NOX emissions from a Euro II petrol car relative to vehicle speed

0

50

100

150

200

250

300

350

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130

Speed (km/h)

CO

2 em

issi

ons

(g/k

m)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130

Speed (km/h)

NO

x em

issi

ons

(g/k

m)

Findings

15

48. The effects of speed on carbon monoxide,particulates and hydrocarbons are less clear butmeasures which increase frequent acceleration anddeceleration produce an increase in these emissionsand in fuel consumption in general (see annex).Measures designed to smooth the overall drivingpattern have shown some benefits, but not as greatas those which can be achieved for oxides ofnitrogen. In some circumstances the changes inspeed during a journey produce more pollutantsthan the steady state speed of the rest of thejourney. We need more information about theoutput of pollutants at smooth slow speeds asopposed to stop-start congestion.

49. We are able to estimate the effects on airquality of any measure which reduces the totalvolume of traffic or changes the fleet composition.Schemes to reduce speed can also have someinfluence on traffic volume. There has been someresearch in this area and TRAMAQ, the trafficmanagement and air quality study (Cloke et al1998), is investigating further. Examination of roadhump schemes shows on average some 25% oftraffic may be diverted from traffic calmed areas.

NOISE

50. Noise from transport is a major concern formany people, especially for those who live close tofast or busy roads, or in inner city areas. There arethree major sources of noise: the vehicle’stransmission; the tyres in contact with the road;and loose bodywork.

51. Two of these are directly related to speed.Engine noise predominates at slower speeds. It isprogressively being reduced as the effect of tighternoise standards for new vehicles works its waythrough the fleet, though this is offset to someextent by increased traffic volumes. Tyre noisebecomes a problem at higher speeds (over 30-40mph for newer cars). The EU has publishedproposals to establish noise limits for tyres incontact with road surfaces.

52. The road surface itself is becoming quieterand safer with new techniques and materials.

53. Traffic calming will generally reduce trafficnoise because of the lower speeds, unless drivingstyle is harsh.

The effect on qualityof life54. Speed of traffic affects people’s quality of life,but these effects are difficult to quantify. Somepeople simply enjoy driving fast. For others, ashorter journey time means access to wider choice,for instance of places to work, shop or pursue sportsand other leisure activities. In urban areasparticularly, journey times can mean the differencebetween whether or not a trip is viable.

55. Of the disadvantages, injuries and noise areperhaps the easiest to measure. It is harder to pindown the effects that fear of fast moving vehicleshas in discouraging people from walking, cyclingand horse riding, or in limiting their enjoyment ofor ability to reach facilities.

56. Long streams of fast traffic contribute to theseverance of communities. This disproportionatelyaffects those who find it difficult to cross fast roads,for example older people and children. In its mostsevere form this can increase inequalities and causesocial exclusion in communities by making it moredifficult to form support networks and, for thosewithout cars, to get to necessary facilities, such asshops, schools and medical services (Department ofHealth 1998a, Health Education Authority 1988).The social price of speed, does not fall evenly.Levels of pollution and general public health areworse in inner cities and there are higher thanaverage child road casualty rates in poorerneighbourhoods (Christie 1995).

57. At slower speeds there is a balance to bestruck between road safety, an environmentconducive to healthy activity and limitingdamaging emissions.

Health58. Accidents and pollution affect health. Speedcontributes to both injuries in collisions and


16

harmful emissions. Particulates, carbon monoxideand hydrocarbons not only seriously affect theenvironment, but also the health of those breathingthe air (see for example, Department of Health1998b).

59. Physical activity is important in reducingheart disease and strokes (Department of Health1999). If the effect of traffic speeds is to dissuadesome people from walking and cycling, this couldaffect their health and general fitness.

The economy60. Time savings are an important economicelement in assessing the case for investment inroads or public transport. Measures which reducemaximum permitted speeds will increase journeytimes in many cases. Indeed, they will increasethem in all cases where they reduce average speedsand so reduce road accidents.

61. For commercial and business users the costs of longer journey times can be measured directly interms of wage rates and the capital tied up in thecommercial vehicle fleet. For other transport users,there is a value for time savings established througha mix of survey techniques and observation oftravelling behaviour.

62. We can show how policies on speedmanagement will influence journey times usingtransport and traffic models, which are amathematical representation of travellers’behaviour. Changes in journey times, combinedwith the values of time savings, give a measure ofthe economic costs for users and allow us tocompare options. We can also estimate the effecton vehicle emissions from the same models.

63. Increasing congestion on urban and someinter-urban roads has made it difficult for drivers toestimate how long their journey will take. We areworking on establishing a value for improvingreliability. Some speed management measuresmight make arrival times more predictable, but wedo not yet have a clear method of assessment.

64. The costs of speed management need to beweighed against the benefits. The greatest potentialbenefit is reducing road casualties. In common withmany other countries, the UK assigns a value to astatistical life and to different categories of injurywhen assessing the case for investment in roadsafety improvements (DETR 1999b).

What people say andwhat they do

SPEED MONITORING

65. Almost all drivers and riders exceed speedlimits at some time. The table below shows theresults of speed monitoring on main and distributorroads (DETR 1999c). There is little information onthe speeds actually being driven elsewhere.

Findings

17

66. Other relevant findings are:

• 19% of car drivers exceed 80mph on motorwaysand 14% on dual carriageways; and

• on rural single carriageway roads, 17-30% ofHGVs exceed 50mph.

ATTITUDES AND BEHAVIOUR

67. Despite this evidence, when drivers arequestioned:

• 84% say the speed limit in town should bebroken only in exceptional circumstances;

• 58% say the same of motorway speed limits;

• 39% of self-confessed speeders favour a threemonth ban for people going 30mph above themotorway limit;

• 36% of them say the same of drivers doing10mph over the residential area speed limit.

(Lex Motoring Services 1997)

68. Even so, drivers and riders often do not knowwhat the speed limit is or understand the reasonsfor it (Silcock et al 1999). Many people do notregard breaking the speed limit as a criminal act.

69. In the absence of police enforcement, manydrivers may not check the limit in force or theirown speedometers. There is evidence that thegreatest influence on the speed they drive is theirperception of the road environment and what feels‘fast enough’.

70. But perception depends much on context.What feels right to the driver or motorcyclist oftenseems too fast for the same people when they arewalking, cycling or when they are judging asresidents of the area.

71. In a survey of 1,022 people asked their viewson country lanes 65 percent said that they feltthreatened by traffic either some or all of the timewhen walking, cycling or riding on these roads(CPRE 1999). The definition used of a countrylane was those classed as C and unclassified roadsin rural areas.

Deciding what speeds areright72. The current national speed limits havedeveloped over many years. They are set out in theannex along with the signs used to indicate them.On some roads, different limits apply to differentclasses of vehicle for safety reasons.

Percentage of drivers exceeding the speed limit on different types of road

Road type Cars Motorcycles HGVs

Motorways 55% no data at present few (1)

Dual carriageways (2) 54% no data at present 79-93%

Rural single carriageways (3) 10% no data at present 60-76%

40mph urban roads 26% 35% 7-16%(7% of busesand coaches)

30mph urban roads 69% 63% more than 50%(41% of busesand coaches

Notes

1 Few HGV, bus or coach drivers should exceed maximum speeds if their speed limiters are set properly.

2 70mph limit for cars, 50 mph for HGVs.

3 60mph limit for cars, 40mph for HGVs.


18

73. Local traffic authorities are free to changethese limits if they feel that they are inappropriatefor some of the roads which they cover. The DETRand Scottish Executive issue advice on setting localspeed limits. The current advice is Circular 1/93issued by the then Department of Transport in1993 and in Scotland SOID Circular 1/93. Theyexplain what to take into account when decidingthe speed limit appropriate for a road. The circularsalso advise authorities to monitor vehicle speedswhere they have changed limits and advise themon measures to bring speeds in line with the newlimit if they are too high.

74. Surveys of road safety professionals anddrivers alike indicate that existing speed limits arenot (in the drivers’ view) consistently applied.Similar roads are given different limits, whichencourages disrespect for speed limits and the lawand is cited as a justification for speeding (Silcocket al 1999).

75. The current advice on setting limits is basedon road safety considerations and does not coverthe wider impacts of speed.

76. No formal assessment is made of theeconomic, environmental or social effects(including road safety) of any change in speedlimits and vehicle speeds. No appraisal frameworkis tailor-made for such a task, although the DETR’snew approach to appraisal (NATA) (DETR 1998)used for assessing road schemes shares the sameobjectives.

Current measures forinfluencing vehicle speeds

ENFORCEMENT AND PENALTIES

77. Speed cameras are particularly effective atreducing vehicle speeds. A Home Office researchreport shows that speeds at camera sites werereduced by an average of 4.2 mph and accidents by28% (Hooke et al 1996). But their effectiveness isblunted by the cost of their operation.

78. DETR and other interested authorities aredeveloping a pilot scheme for a new financialsystem which will allow the additional cost ofcamera enforcement to be funded from speedingfines. HM Treasury has set the rules for the twoyear pilot which will start in April 2000 in eightpolice force areas.

79. If the results are satisfactory, we will develop asystem for the police, courts, local authorities andothers to reclaim the costs of buying additionalcameras, or increasing the use of existing ones,where otherwise no funding would have beenavailable.

80. Even where they can be used fully, camerasshould not be regarded as a panacea. Motorists tendto slow for cameras and increase their speed oncepast.

81. For speeding offences, the courts can:

• endorse driving licences by between 3-6 penaltypoints;

• disqualify drivers in the most serious cases; and

• impose a fine of up to £1,000 (£2,500 formotorway offences).

82. In addition to the offence of ‘exceeding thespeed limit’ it is possible for speeding motorists tobe charged with the more serious offence of‘dangerous driving’ or ‘careless and inconsideratedriving’ (Section 1 & 2 respectively, Road TrafficAct 1991) where much heavier penalties couldapply. On motorways, speeding is a higher categoryof offence than when it occurs elsewhere.

83. In practice most speeding offences are dealtwith through the fixed penalty system where adriver is currently fined £40 and has 3 points addedto their licence. A driver who gains 12 points ormore is disqualified. New drivers with 6 points havetheir licence revoked.

TRAFFIC CALMING

84. Road humps, chicanes and other roadengineering measures remain the most effective

Findings

19

method of reducing vehicle speeds in urban (andsome rural) areas. They can reduce average speedstypically by 10 mph (Mackie 1998), and areparticularly effective at reducing child pedestriancasualties. Schemes can be designed to encourage asmooth driving style to limit noise and emissions.There is no evidence that when negotiated atsensible speeds these cause damage to vehicles. Butthey cannot be applied everywhere, such as onmajor through-routes, especially if regularly used bythe emergency services.

85. Road markings have been used to good effectfor changing the nature and appearance of a road,and the speed at which people choose to drive.A good example is hatched centre line markingswhich can give the impression that roads arenarrower. Research is currently in progress to seehow road markings at bends could give betterguidance to drivers.

86. The additional speed limit signing currentlyin use, such as countdown signs (placed at regularintervals before a limit), has had little effect onvehicle speeds. Carriageway roundels (speed limitsigns painted on the road) have had somebeneficial effect when used with upright signs atthe start of speed limits. As repeater signs, theyhave not brought about significant speedreductions. It is difficult to see them at night orwhen they are wet or obscured. Both signs requireapproval before they can be used.

87. There are new types of sign which have shownreal benefit. They are activated by individualvehicles approaching a hazard such as a bend orobscured junction above a set speed, or travellingabove the speed limit. They may show the advisedspeed, or a sign indicating the nature of the hazard,or a road safety message (see for example Compte1998, Farmer et al 1998). These vehicle-activatedsigns have proved effective at reducing vehiclespeeds and collisions at certain sites.

88. The work of the countryside traffic measuresgroup (CTMG) includes finding sympathetic trafficmanagement measures for use in rural areas. So farit has been difficult to identify measures that areboth effective and acceptable to local residents.The Scottish Executive is also researching into theprinciples of ‘sympathetic’ traffic calming.

89. Collisions on rural roads tend not to beconcentrated at specific locations but scatteredalong sections of road. DETR-commissionedresearch indicates that accident rates per junction,per bend or per vehicle-kilometre might be usefulways to prioritise areas for remedial treatment. Wegive local traffic authorities accident rates based onnational figures for different classes of rural road.They provide a benchmark for authorities to use assuggested intervention levels for their own roads(Barker et al 1999, IHT 1999). DETR will shortlybe issuing advice on using the intervention levels.

EFFECT OF SPEED LIMITS

90. Speed limits on their own have little effect onvehicle speeds. In places where speed limits havebeen reduced and no other action taken, the changein mean traffic speed is observed to be about aquarter of the change in posted speed limit. Forexample, changing a limit from 40 mph to 30 mphtends to reduce speed by 2.5 mph (Finch et al 1994).

91. Experience from Suffolk indicates thatcasualties can be reduced by introducing county-wide rural speed limits. (Suffolk County Council1997, Watson 1999). Some other counties arefollowing suit, but there is no national guidance onwhat is an appropriate speed nor how it may beachieved.

92. Following changes in legislation in 1999,local authorities are free to introduce self-enforcing20 mph zones and 20 mph speed limits where theseare likely to reduce actual vehicle speeds and cutcasualties.

93. Currently, the most effective way to reducevehicle speeds to 20 mph or less is throughengineering measures. Without traffic calming,reducing a speed limit to 20 mph has not beeneffective. It usually slows most vehicles by only 1 mph (Mackie 1998). In Scotland 75 pilot projectsare testing the effectiveness of 20mph schemeswhich do not include traffic calming in areasmainly used by the people that live in them, andwithin little through traffic. The results are due inthe Summer of 2000.


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94. Graz, in Austria, had been progressivelyintroducing 30 km/h (approx. 20 mph) zones withtraffic calming for 10 years. But the waiting list forzones was increasing faster than they could beinstalled. In 1992, Graz decided to introduce ablanket 30 km/h speed limit on all non-throughroads. The remainder kept their 50 km/h limits(approx. 30 mph). This was part of a localintegrated transport strategy called ‘gentle mobility’which aimed to promote walking, cycling andpublic transport and to limit car travel withoutinterfering with business.

95. Intensive public awareness work and policeenforcement accompanied the introduction of thelower limits. Public approval levels increased fromless than half to over three quarters after four years.

• Casualties decreased by 12% city-wide.

• Mean speeds between junctions reduced by 0.5 km/h and at junctions by 2.5 (8%).

• 85% of traffic reduced speed by about 2 km/h at junctions and 1.6 km/h between them.

• The proportion of those travelling above 50 km/h fell from 7.3% to 3% with the newlimit (Wernsperger and Sammer 1995).

96. But when enforcement stopped speedsgradually increased to near their previous levels.

HOME ZONES

97. Home zones, now common in many parts ofEurope, originated in the Netherlands. They areusually an area of residential streets in which theroad space is shared between motor vehicles andother road users, with the needs of pedestrians andcyclists coming first. The DETR is exploring theextent to which home zones can be implementedwithin existing UK legislation. The three yearmonitoring project covers nine local authorityschemes in Ealing, Lambeth, Leeds, Nottingham,Manchester, Monmouthshire, Peterborough,Plymouth and Sittingbourne.

98. The Scottish Executive has announced itplans similar monitoring in Scotland.

SPEED LIMITERS

99. Speed limiters are already fitted to somevehicles to restrict their maximum speed. Forexample HGVs have governors limiting them toeither 56 mph or 60 mph, depending on theirweight. However, it is possible to keep speeds to thespeed limit in force on any given road, rather thanjust the maximum speed possible. The technology isalready available to detect speed limits using adigital map kept in the vehicle. The globalpositioning system (GPS) identifies the vehicle’slocation by satellites. These systems can be used toinform drivers of the limit, or they can link into anadaptive speed control system. But their general use,even if adopted, is some years away.

CHAPTER 3

Analysis

100. Analysis of the review’s findings is dividedinto sections discussing:

• the effects of speed;

• the problems to be tackled in urban and ruralareas and on motorways; and

• measures to achieve appropriate vehicle speeds.

101. Given the obvious conflicts, the analysismakes it clear that when improving road safetyspeed management policy for any given road willnot benefit every objective of A New Deal forTransport. A balance needs to be struck. The newapproach to appraisal of road schemes announcedin the white paper provides a means of describingand often quantifying the benefits and drawbacks ofpolicies to manage vehicle speeds.

102. Some policy options require further researchand analysis before their effects on the economy, onsafety, accessibility and the environment can bedetermined reliably and the results presented in theform that is now being used to appraise othertransport projects and policies.

The effects of vehiclespeeds

ROAD SAFETY

103. Speed is not the only factor in collisions.Many accidents have more than one contributorycause. DETR and the Scottish Executive areworking to tackle other areas such as drink-driving,seat belt wearing, driver training, and pedestrian

awareness. The road safety strategy, Tomorrow’sRoads : Safer for Everyone explains the measures indetail.

104. That said, the speed review has confirmed thefollowing points.

• Speed is indeed a major contributory cause ofcasualty accidents. Recent research has addedgreatly to our knowledge of where the problemsare particularly acute (see para 35 onwards).

• Slowing the fastest drivers will yield thegreatest safety benefits.

• In some areas quite small reductions in averagespeed would bring large benefits.

• Speeders are disproportionately involved incollisions (para 39).

• Those that drive faster than most on a road, or exceed speed limits even by relatively smallmargins greatly increase the risk to themselvesand others.

• The higher speeds on any given road areassociated with both more accidents and greaterinjury severity. This relationship holds for alldrivers and not just the less experienced.

• The faster the speed at impact the more severethe resulting injury. This is particularly so forcollisions with pedestrians, cyclists andmotorcyclists, who are unprotected from theforces of impact unlike occupants of moderncars (para 42 onwards).

• Some people do not accept that speed is aproblem. Even those that say they do, do notalways act accordingly.

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Analysis


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• Drivers often do not understand why speedlimits are set as they are. In some cases it maynot be clear to them what the limit is.

WIDER IMPLICATIONS OF VEHICLESPEEDS

105. From the available evidence there are somevery clear messages on the impact of speed on thewider objectives of integrated transport.

106. Air quality and noise are important in urbanareas where the problems tend to be worse andmore people are affected. Speed management aimedto improve road safety in urban areas may affectnoise and air quality. Schemes should aim tominimise adverse effects.

107. Some measures to improve road safety canalso improve air quality and noise levels. This isperhaps more so in rural areas where speeds arehigher.

108. We need more work to establish the effect oftraffic management schemes (like road humps) onair quality in order to produce clear guidance fordecision makers (para 49).

109. At lower speeds, traffic calming may increaseemissions of greenhouse gases and most airpollutants, but careful planning and design canminimise the effect on air quality (para 84).

110. Smooth driving without fast acceleration anddeceleration is less polluting than harsh driving(para 46).

111. Speed management policies can help reducenoise originating from tyre contact with the road.Generally the higher the speed the greater theproblem.

112. Better vehicle standards are cuttingtransmission noise. These improvements should notbe counteracted by traffic calming schemes. Whenthey are carefully implemented, the lower speedsusually result in less traffic noise.

113. Increases in journey times brought about bylower average speeds increase road transport costsfor all users and especially business and industry(para 60 onwards).

114. There are other areas, particularly in relationto the impact on quality of life and suppression ofalternative modes of transport, where we need moreinformation to guide policy decisions. We also needa more thorough breakdown of how fast people aredriving and riding on all the different types of road.

Urban speed management

WHAT SPEEDS ARE APPROPRIATE?

115. Most injuries occur in urban areas, althoughthis is not the case for deaths (para 27). In free-flowing traffic the road safety evidence points tothe need for slower driven speeds on most urbanroads, particularly main roads. These account forhalf the casualties because of their mixed use bytraffic and pedestrians. It is also here that there arethe greatest air quality and noise problems. So, dowe need changes in the speed limit, or would weachieve the required outcome if more peopleobserved the existing limit?

116. The 30 mph speed limit has been with ussince the 1930s. It is universally acknowledged andenjoys a great deal of support with few wanting anincrease. About a quarter of people favour lowerlimits. This is at odds with the speeds of themajority of drivers and riders in free flowing trafficon many urban roads.

117. Some favour lowering the urban limit to 20 mph. Some favour reductions on certain classesof road only, most notably residential roads, thosearound schools, hospitals or similar areas. There is astrong road safety case for vehicle speeds closer to20 mph in areas where the vulnerable, especiallychildren and older people, are most likely be atrisk. In key areas this would also supportgovernment policies for urban regeneration.

118. But if vehicle speeds were now lowered to 20 mph on all roads currently restricted to 30 mph,emissions of CO2 and some air pollutants would

Analysis

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increase markedly (para 47 onwards). This wouldbe unacceptable at a time when the governmenthas a legally binding target to reduce greenhousegas emissions and a domestic goal to cut CO2

emissions.

119. The cost to the economy in increased journeytimes arising from generally slower speeds is alsolikely to be noticeable. Plowden and Hillman(1996) attempted to quantify time and costpenalties from enforcing lower speeds in urbanareas. They conclude that much work needs to bedone in this area of modelling, especially as thepotentially positive effects on pedestrians, cyclistsand on drivers entering the traffic stream from theside roads have not so far been included.

120. The aim in urban areas should be speed limitsappropriate for the roads to which they are applied.On some the benefits of speeds as low as 20 mphwill outweigh the disadvantages. On others a limitof 30 mph (if observed) will strike a suitablebalance between safety and other considerations.Elsewhere an objective study may conclude thatsome 30 mph roads could safely sustain a 40 mphlimit. These would need to be:

• areas where few pedestrians and cyclists couldbe expected; or

• where there is ample provision for all those thatneed to use the road safely; and

• there are no additional disadvantages in termsof vehicle emissions, especially noise.

ACHIEVING APPROPRIATE SPEEDS

121. This argues for local traffic authorities totarget speed management in urban areas. They arein the best position to identify and treat problemareas. This approach would ensure that the fulllocal impact of every scheme could be assessed.

122. Where speeds of 20 mph are necessary, self-enforcing 20 mph zones have proved verysuccessful. All research to date into the relationshipbetween speed limits and vehicle speeds points to20 mph limits being relatively ineffective withouttraffic calming (see para 94). So self-enforcing

zones should continue to be the norm. There is stillplenty of scope for installing them. We do not havetraffic calming around the majority of schools forexample.

123. Within town centres and other areas with amixture of land uses, planning guidance alreadyrecommends that priority should be given to peopleover traffic. Well designed pedestrianisationschemes generally prove popular and commerciallysuccessful, and local authorities should considertraffic calming and reallocating road space topromote safe walking and cycling and to givepriority to public transport.

124. All speed management schemes should bedesigned to be sympathetic to their surroundingsand, wherever possible, used to enhance an areaaesthetically. This would be in keeping with thegovernment’s aim to make cities and townsdesirable and attractive places to live. But trafficcalming must be conspicuous to be effective and it is likely to prove challenging to produce entirelysympathetic designs.

125. We need continued research to find ways toencourage drivers to reduce speeds withoutengineering measures. The most pressing need is tomake drivers comply with existing speed limits.

126. We need other research too, to help developour national speed limit policies. One example isthat speed monitoring data tends to cover onlymain and local distributor roads. Details of thespeeds driven (and therefore the extent of theproblem) elsewhere is scarce.

127. More work needs to be done to:

• establish the range of vehicle speeds across thewhole urban network;

• identify where excessive and inappropriatevehicle speeds are a road safety problem; and

• identify and develop measures to achieveappropriate speeds, especially in areas where wecannot use traffic calming. We need to workwith local traffic authorities, particularly onassessing costs.


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128. To summarise: in urban areas we believe that,in general, the problem is that drivers exceed thecurrent speed limit rather than that the limit itselfis too high. Where a 20mph limit is needed, to beeffective it should be self-enforcing.

URBAN SPEED LIMIT SIGNING

129. The national speed limit of 30 mph (therestricted road limit) is applied by law to any roadin England and Wales with a system of streetlighting in which lights are no further than 200yards (183 metres) apart. Exceptions are where alocal traffic authority has applied a different limit.

130. In Scotland the limit only applies to Class Cand unclassified roads with lighting no more than185 metres apart.

131. Signs are required to show the start and finishof the limit, but repeater signs are not permitted onthese roads. This is because of a legal ruling thatrepeaters on some roads and not others can makedrivers uncertain of the speed limit in force.

132. At first sight, this would seem a rather odd wayof indicating a limit. But in practice it has the meritof simplicity: if there are street lights and no signs tothe contrary, then the speed limit is 30 mph. It isdifficult to find an alternative way of defining theseareas in law. Other legislation tends to define ‘urbanareas’ as those with a 30 mph speed limit.

133. Sometimes people claim the absence ofrepeaters is a reason for speeding. We accept some30mph roads might look to motorists as thoughthey would have a higher limit. We might needlegislation to reverse the long standing principleand permit repeater signs on such roads.

134. It would be wise for local traffic authorities toassess whether the speed limit is appropriate beforeinstalling repeaters under any new powers. It isunlikely to be acceptable to insist that vehiclestravel at 30 mph on, say, a dual carriageway justbecause there are street lights. Repeaters would notaffect driven speeds.

Rural areas

STRATEGY FOR RURAL ROADS

135. At present the problems on rural roads mostlyconcern vehicle speeds that are within the currentlimit but inappropriate for the conditions. So, doesthe speed limit need to be lowered or does thesolution lie in the use of other measures?

136. The national speed limit on singlecarriageway roads in rural areas is 60 mph for carsand motorcycles. A number of influential groupscall for reduction in this limit on all the roads towhich it applies. Most prefer a new limit of 50mph. Others would like to see an even lower limit,or additional limits applied to different types ofrural roads. Other groups oppose any reduction.

137. It is clear that we need a consistent strategyfor managing vehicle speeds on all rural roads.There is general agreement that co-operationbetween the highway authority, local people andthe police is required – and the implementation of the new IHT guidelines for rural safetymanagement (IHT 1999) – is necessary to achievethis. The current classification (A, B, C andunclassified) would not offer a complete solutionbecause the classifications were developed to definedirect routes between main destinations rather thanto describe the quality of the roads.

138. In the longer term the goal should be todevelop a method of defining a road hierarchy forspeed management purposes. This would benefiturban as well as rural areas. More immediatesolutions will need to be found.

139. For the purposes of the review, we divide ruralareas into three categories: main roads; villages; andcountry lanes. These are generalisations. Reality isa lot more complicated.

MAIN ROADS IN RURAL AREAS

140. Where rural single carriageway roads areconcerned, discussion about speed limits tends tofocus on the national speed limit of 60 mph for cars

Analysis

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and motorcycles. This is relatively well observedcompared with other limits (para 65).

141. There is a case for reducing the nationalspeed limit and retaining a higher limit on betterquality roads. There is a substantial cost involvedin this option because we would have to advisemotorists of any new speed limit in force, eitherthrough sustained national and local mediacampaigns, or by changing the speed limit signs onall the roads affected. So, would the benefitsoutweigh the costs or would it divert resources frommore effective solutions?

142. The safety problem on these roads is clear.Many collisions are the result of either overtakingor of driving too fast to negotiate a hazard like abend or junction (Barker et al 1998). The victimsare mainly drivers and passengers. The researchresults so far indicate that better control of vehiclespeeds at hazards such as bends and junctionswould be a more effective way of reducingcasualties on rural main roads than a reduction inthe national speed limit (Taylor et al 2000).Fortunately the relatively low cost technology to dothat has been developed. Sensors which detectvehicles approaching too fast and give the driver awarning sign (para 87) are being tested in Norfolk.

143. Looking at wider objectives the prioritiesmust be:

• to make other road users feel safer; and

• to improve the quality of life of people who livein or visit rural areas.

• Noise is less of an issue as there are generallyfewer people affected.

144. The solution is not straightforward. Howmuch more slowly would vehicles need to go tomake other road users feel safer? We do not yetknow whether cutting vehicle speeds to 50 mph(or even 40 mph) would be enough to encouragewalkers, cyclists and horse riders to use such busyroads more, even if there were provision for them.We need to study some local projects to find out.

145. If we could assess the best speeds for theseroads, there is still the question of how to bring

vehicle speeds in line with it. There is evidencethat drivers are confused about the national ruralspeed limit. The nature and appearance of the roadis one of the strongest influences on how fastpeople drive, and therefore the speeds currentlydriven on rural roads. If a lower speed limit wereimposed without any additional speed managementmeasures, drivers attitudes would have to changefor there to be a general reduction to the new limit.

146. On balance it seems sensible not to makeblanket changes to the national speed limit atpresent. Instead, local authorities should developspeed management strategies, taking into accountnational guidelines and local conditions. Somelocal authorities have already decided to reducelimits on many of their roads. There will certainlybe some further speed restrictions as well asmeasures at hazardous locations. The advice weplan to issue on intervention levels (para 89) willhelp local targeting.

147. There is a growing consensus that the sign toshow that the national speed limit applies (seeannex) is misleading, or at best not properlyunderstood. In part this may be because themeaning of the sign has changed since it was firstintroduced to show the road was ‘de-restricted’. Weneed to find a more effective method of informingdrivers of the speed limit on these roads.

VILLAGES

148. There are three questions relating to villages:

• how should they be defined;

• how can we make sure vehicle speeds are nottoo high; and

• are the measures available acceptable?

149. High vehicle speeds severely disrupt ruralcommunities. In villages, fear of traffic can affectpeople’s quality of life. The case for some biggervillages to have the same speed limit as similarroads in urban areas is self-evident. We believe itshould be regarded as the norm. But a speed limitdoes not necessarily reduce vehicle speeds in line.Drivers cannot be expected to respect limits nor


26

understand the reason for them if they are seen tobe arbitrarily applied or gradually encroaching onhigher quality roads into the countryside.

150. Before a national speed limit could be appliedwe have to reach agreement as to what constitutesa village. Some settlements are very small. Arriving at a workable definition will take localconsultation, as well as research and discussion at a national level between departments and localauthority associations.

151. Some form of traffic calming is usuallyrequired to reduce drivers’ speed through villages.People who want lower limits often dislike thesesort of measures and even dislike the signingrequired to tell motorists what the limit is. So thereis a conflict to be resolved. Some local authoritieshave now taken the decision to lower speed limitsin all their villages and we will want to see howwell they fare.

COUNTRY LANES

152. The one aspect of the national speed limitsystem that comes in for most criticism is thenotion that 60 mph is a reasonable maximum speedon country lanes.

153. On single track and narrow roads such highspeeds are clearly not desirable, and often notachievable. On such roads any speed limit isacademic. The threat of prosecution for theoffences of dangerous driving or driving withoutdue care and attention might be a better deterrentagainst bad drivers.

154. On country lanes, the speed limit is onlyrelevant where it is possible for drivers to break itand where the appearance of the road leads them todo so.

155. It is often suggested we set a lower nationalspeed limit for these roads. But how could they belegally defined? What constitutes a country lane?Given that signing is such a sensitive issue in thecountryside, how would we make the limit clear todrivers? These questions are yet to be answered.

156. We need more information before we canproperly assess the case for a lower national speedlimit. In particular research needs to establish whatthe vehicle speeds are on these roads, and theeffect they are having on walking, cycling andhorse riding. Without this knowledge, it is not clearwhat the limit should be or what effect it wouldhave on how fast people drive, given significantpolice enforcement is unlikely. Again, someauthorities have already established lower speedzones and we will learn from their experience.

157. So, at the moment it makes sense only totreat the roads where local authorities can identifythat problems exist, using lower local speed limitswhere needed. Elsewhere, it is not a problem if thenational speed limit is higher than the speedspeople can actually drive. Resources should not bespent on a road if speeds are effectively restricted byits nature. There is clearly a need to explain thisapproach. Having done so it should not affect thegoal of gaining respect for limits as a whole.Arguably, this is most likely to be jeopardised bylimits that are set too low.

Motorways and dualcarriageways158. From a road safety perspective the mostdangerous aspects of dual carriageways andmotorways are:

• congested periods;

• the points where drivers join and leave them;and

• speed through road works.

159. In free-flowing traffic, strategies for theseroads will still need to take account ofenvironmental and economic objectives.

160. On motorways the accident rate is goodcompared with other roads. This is because they areof a consistent and high standard. Vehiclestravelling in different directions are segregated andthe most vulnerable of road users are prohibited.

Analysis

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161. There are strong views on the presentmotorway speed limit of 70 mph. It is broken by55% of car drivers. It is not practical to enforce iteverywhere. So there is some pressure to raise it to80 mph, although many professional groups,including the Association of Chief Police Officersand the AA, do not support this view.

162. There is convincing evidence from the USAthat where some freeway speed limits have beenraised and vehicle speeds increased there have beenmore casualties (Farmer et al 1999). It is notcertain what the effect would be here, but it is atleast likely to be the same, especially if motoristswere to break the new limit by much. Any rise inthe speed of the faster vehicles would increase thedifferential between them and the slowest (HGVsmostly).

163. There is no doubt that any increase in vehiclespeeds would increase emissions of CO2 and NOx,and generate more noise. Decreased speeds wouldhave economic effects through increased journeytimes.

164. But lower speeds do not always increasejourney times. The controlled motorway projectbeing trialled on the M25 (see annex) appears tobenefit drivers by smoother traffic flow and morereliable journey times.

165. In free-flowing conditions on motorways anddual carriageways we believe that the current speedlimits strike the right balance between thecompeting priorities. The problem lies in gainingcompliance.

Achieving appropriatevehicle speeds166. Deciding what speeds are appropriate is onething, achieving them is another. This sectiondiscusses the merits of current measures and futureinitiatives.

A STRATEGY FOR SETTING ROAD SPEEDLIMITS

167. Ultimately the goal for speed managementpolicies must be for drivers to take responsibility fortheir own actions and abide by speed limits. Forlimits to be respected they not only need to beappropriate for the road, but also to be understood.Inappropriate limits are often ignored and makedrivers less willing to comply with the systemgenerally.

168. Speed limits can be set nationally or locally.There are advantages and disadvantages with bothsystems. Simplicity is a major benefit of a nationalspeed limit: it is applied to all roads of a particulartype. There is, though, a great variation withincategories such as rural single carriageways andurban roads. This leads to inconsistencies.

169. Local traffic authorities have powers tochange any speed limit on their roads. Despitenational advice, drivers and riders can experiencedifferent speed limits on similar roads depending onthe part of the country in which they are driving.This in itself can lead to disrespect for the system.We need policies that ensure consistency as far aspossible throughout the country. It will not be easyto achieve: councils have to react to local pressuresas well as professional advice. The decisions mustremain local.

170. Consistency is extremely important. If publicperception is that speed limits are wrong or set atthe whim of the local authority this will make itparticularly difficult to change attitudes to speedingthrough education and publicity. Enforcement andpenalties would appear unduly harsh.

171. Another difficulty for local traffic authoritiesis the time and cost involved in making individualspeed limit orders. A simplified method of applyinglimits locally would help. Local authorities wouldbenefit from the power to translate speedmanagement strategies more easily into speedrestrictions.


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SPEED MANAGEMENT MEASURES –BENEFITS AND LIMITATIONS

172. The majority of current speed managementmeasures are very effective on certain types of road(see para 84). There is scope for applying somemeasures such as road humps and 20 mph zonesmore widely, where their benefits outweigh anydisadvantages.

173. Speed cameras are not being used to their fullpotential because of the cost of operating them(para 77). If the funding problem can be overcome,more cameras should be used to cut collisions.Cameras already in place could be more effective ifthe trigger speeds were reduced to thoserecommended by the police.

174. With the exception of the controlledmotorway experiment, speed cameras are used onlywhere they can improve road safety. This shouldremain the case, if we are to keep public support.

175. Signing and road markings are the areaswhere we have the least success at the moment.Longer term they have the most potential. On itsown, extra signing such as carriageway roundels,countdown signs, or additional repeater signs hasonly a small effect on vehicle speeds. Evidencefrom The Netherlands suggests that a co-ordinatedapproach to this kind of signing may be moreeffective. It could be an answer to the problem thatsome roads by their appearance give motorists theimpression that it is safe to drive at a speed higherthan the limit in force.

176. Ideally, drivers should themselves choose todrive at the speed which safety, environmental andsocial reasons would dictate. Road design, includingsigning and marking, should help them. We needmore information about which features mostinfluence drivers’ choice.

SPEED LIMITERS – VEHICLE CONTROL

177. As a longer term measure adaptive speedlimiters (para 99) offer three potential benefits, to:

• advise the motorist when the limits change;

• allow the motorist to stop themselves goingbeyond the limit; and

• prevent the motorist from exceeding limit.

178. There is significant potential for casualtyreductions. Findings suggest collisions could dropby 20% if all vehicles kept within present speedlimits (Carsten 1999). Not only would a mandatorysystem prevent speeding, it would also allowvariable speed limits in bad weather or at night,and lower limits at hazards like junctions and bends– this could result in a 35% reduction in collisions.It would free the police and the courts toconcentrate on other offences, and deliver hugesavings in casualties, emissions and the cost ofenforcement. It might also be possible to increasesome limits in the knowledge that they could beenforced.

179. But there is a big question about theacceptability of this equipment to the public. It would also be some time before it could beintroduced on all vehicles. Performancerequirements for the equipment would have to beestablished. Vehicle construction standards aregoverned by EU regulations, which could affect anyrequirement for vehicles to be fitted with suchequipment. Discussions have started on producingperformance requirements for manufacturers whomight wish to offer this technology.

180. The best way ahead is likely to be forinterested manufacturers to offer the equipment to customers as a way of staying within the law. If a significant number of motorists take up fitmentvoluntarily, a future administration could considermaking it mandatory.

BENEFITS OF BEHAVIOURAL CHANGE

181. Speed limiters have their attractions, but itwould be much better to persuade drivers to changetheir behaviour. If we are to reduce the need fortraffic calming and enforcement, and particularly tomoderate speeds in remote areas, individual driversneed to take responsibility for their own actions. It would benefit both safety and the environment.

Analysis

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182. But speeding is endemic. The monitoringresults (table, para 65) show it.

183. We must explain properly the risks of speedand the reasons for limits and persuade drivers topay attention to them. Perhaps there are betterways than roadside signs and speedometers toremind drivers what the limit is and how fast theyare going. We must also try to explode some of themistaken beliefs: experience, vehicleimprovements, or empty roads at night do notmake speeding safer. We must shift public attitudesand persuade drivers to behave responsibly all thetime, not just when they think they might getcaught.

184. There are deeper forces at work. There is acachet attached to driving fast. It is seen as ‘macho’which indicates that social and cultural norms areplaying an important part in speed choice (Silcocket al 1999). There is evidence that drivers’perception of their own skill and ability affects thespeed at which they drive. Some people alsobelieve that driving faster somehow sharpens theirsenses and makes them more alert. Some of theseclaims were once made about drink-driving, nowregarded as irresponsible by the vast majority.

185. Limits are still going to seem too low to somedrivers, even if better and more consistently setthan they are now. Advertising campaigns will playa big part in changing attitudes and behaviour.Publicity will also be required to educate driversabout the need for limits for all road users, not justthemselves, and the reasons why they are set atcertain levels.

186. The “Kill your speed” campaign has raisedawareness of the issue of speed. Whilst it is wellrecognised, the indications are that drivers do notunderstand clearly enough what they should do inresponse. We need to address this.

187. Linking insurance premiums in part tospeeding convictions may help raise awareness ofthe danger with motorists, providing an additionalreminder of the link between speed and collisions.Insurance companies currently view speedingoffences as a symptom of the problem of poordriving, rather than including these offences intheir risk assessment. Given the evidence of the

important part speed plays in collisions this may bean area where the industry could make voluntarychanges.


188. We would prefer people to observe speedlimits without a police presence, but enforcement isimportant in speed management. Both enforcementand penalties should aim to prevent re-offending.

189. The Crime and Disorder Act (see annex) willassist speed management policy

190. Fear of penalties can be a potent deterrent,but only if it is not seen as an empty threat. It isunrealistic to expect enforcement everywhere,especially in remote rural areas.

191. It is also important that enforcement is seento be for a good reason rather than as a form ofrevenue collection

192. For the foreseeable future it is impossible tooperate a system of ‘zero tolerance’. We have toallow for the accuracy and calibration of detectiondevices. We would also wish to maintain theprinciple of giving people a fair chance to staywithin the law.

193. This suggests we should retain the currentenforcement thresholds advised by the Associationof Chief Police Officers’ (ACPO) in England andWales and the Lord Advocate in Scotland. But themessage to drivers should be to drive within thespeed limit, rather than at the threshold forenforcement. That leaves no margin for error andcould end in prosecution – or in killing or injuringsomeone.

194. Given the link between speed and accidents,we question whether drivers should be able to runup as many as four fixed penalty offences beforethey are disqualified.

195. Motorists who grossly exceed speed limitsgreatly increase the risk to both themselves andothers. The evidence suggests that much tougherpenalties are required for such an offence. Thesystem should punish the worst offenders more


30

seriously. The present statute which regardsmotorway speeding as worse than speeding onordinary roads is not supported by the evidenceof risk.

196. All the current penalties for speeding aim todeter drivers through the cost of being caught,whether that be financial loss or loss of mobility.Arguably, drivers do not associate this sort ofpenalty with a dangerous or serious criminal act.Surveys undertaken by Corbett et al (1998)indicate that fines at current levels are unlikely todeter the fastest drivers and that more points,heavier fines and a high risk of detection would beneeded.

CHAPTER 4

Recommendations

Overview197. Too many people take a cavalier attitude tospeed. Yet speed is a contributory factor in aboutone third of all collisions. Every year excessive andinappropriate speed helps to kill around 1,200people and to injure over 100,000 more. It is by farthe biggest single contributor to casualties on ourroads.

198. Vehicle speeds are also a factor in airpollution, emissions of green house gases and noise,all of which affect people’s health and quality oflife. Changes in vehicle speeds can affect theeconomy in a number of ways.

199. Most of our current speed managementpolicies are effective. Selective traffic calming andpolice enforcement should continue. The challengeis how to get the right speeds over the wholenetwork rather than at isolated sites. We need theco-operation and understanding of drivers and theirrespect for the system of speed limits.

200. This strongly argues for a national frameworkwhich encourages consistency across British roadswhilst allowing local traffic authorities flexibility to:

• make sure the limit is right for the individualroad; and

• to take into account all local considerationswhich might be affected.

201. From this foundation we could work to changedrivers’ attitudes and behaviour through educationand publicity campaigns and, for those that refuse toheed the message, enforcement and penalties.

202. We need a strategic approach to speedmanagement that:

• considers how different measures cancomplement each other;

• takes account of its contribution to widerplanning and transport objectives; and

• sets a clear and consistent context for it inregional and local transport strategies.

203. It must also take far more account of the roaduser than it has up to now. It is no good havingexcellent speed management schemes if the driveris unconvinced by them.

Action plan204. We propose that the Government:

• develops a national framework for determiningappropriate vehicle speeds on all roads, andensuring that measures are available to achievethem;

• publicises widely the risks of speed and thereasons for limits;

• researches a number of speed managementproblems to develop and test new policies; and

• ensures that policies take account ofenvironmental, economic and social effectswhen assessing their ability to reduce casualties.

31

Recommendations


32

SETTING THE RIGHT SPEED LIMITS

205. We do not recommend blanket changes innational speed limits. But we should revise ourguidance on setting local limits to achieveappropriate, consistent standards across the countrywhich reflect, as far as possible, the needs of allroad users. We suggest the use of a methodologybased on our new approach to appraisal of roadschemes to ensure that when limits are set for roadsafety purposes the wider impacts are also assessed.The guidance would cover sensible measures localauthorities should apply to achieve appropriatevehicle speeds.

206. We suggest the development of a simplermethod of making speed limits by reference to aspeed management strategy (para 171). It wouldwork in much in the same way that structure planslook at strategic planning. We should alsoencourage local authorities to target speed-relatedaccident sites.

New hierarchy207. An additional hierarchy of roads defined byfunction (para 138) would help in setting speedlimits and would improve consistency if variationswere kept to exceptional circumstances. Werecommend it as a long term measure, and woulddevelop it in conjunction with local trafficauthorities. The hierarchy would categorise roads asfar as possible into those whose primary function is:

• the movement of people and goods by vehicle;

• for people to move safely on foot or bicycle;and,

• to cater for both on mixed priority roads.

208. We should take account of the Rural SafetyManagement Guidelines recently published by theInstitution of Highways and Transportation (IHT1999), the IHT Guidelines for Urban SafetyManagement (IHT 1990), and the joint paper RuralRoad Hierarchy and Lorry Routing published in 1997by The Scottish Office and CoSLA which allinclude advice on the development of additionalhierarchies for urban and rural roads.

209. The development of a new hierarchy shouldbe timed to tie in with local authorities’development of future local transport plans.

PROVIDING BETTER INFORMATION

210. We suggest the provision of betterinformation to help drivers, including:

• more effective speed limit signing;

• vehicle activated signs at hazards;

• additional signing for speed cameras; and

• using driving tests and training to give novicesbetter appreciation of what is a safe speed.

ROAD DESIGN

211. We believe there would be real benefit indesigning roads which clearly indicate by theirappearance the speeds which are appropriate. We recommend research to find what aspects of the road environment have most influence on thespeed drivers choose. It will help us develop designprinciples for new roads and assess both thechanges existing ones need and the practicality of modifying them.

HIGH SPEED ROADS

212. On motorways and dual carriageways thesafety record is significantly better than on othertypes of road. It could be better still, and we suggestlooking at ways to improve compliance with:

• the 70 mph limit, especially on sections wherewe know traffic speeds are excessive, increasingthe risk of casualties; and

• lower limits in force for road maintenance ortraffic management.

213. Retaining the 70mph limit would strike abalance between considerations of safety, theenvironment and noise on one side, and theeconomy on the other (para 158 onwards).

Recommendations

33

214. We recommend continuing to develop andmonitor schemes similar to the controlledmotorway system (see annex) where they canbenefit motorists and make the best use of thenetwork. We should also develop measures totackle the problem of collisions at the points wherevehicles leave these roads for other less wellengineered areas.

URBAN AREAS

215. It is not appropriate to lower the 30 mphlimit on all the urban roads to which it applies.Local traffic authorities already have effectivemeasures to treat problem areas. This approachallows them to select measures after fullconsideration of their impact on quality of life, theeconomy and environment, and noise levels as wellas road safety and mobility.

216. There is a very good case for lower speeds insome places, such as residential areas where themost vulnerable road users are. We shouldencourage local authorities to reduce vehicle speedsto 20 mph where this would be appropriate for road safety and urban regeneration. Self enforcing20 mph zones are currently the only effectivemethod of achieving this. We should continue tosupport authorities with guidance onimplementation, especially in support of localcasualty reduction targets.

217. High streets with mixed traffic and diverse usepresent a unique combination of problems. On someof these roads, speeds around 20 mph would be inline with government policies to reduce accidentsand assist urban regeneration. We suggestdeveloping and testing practical measures to acheivethese speeds and reduce pedestrian accidents.

218. At the same time, we should continue todevelop and encourage additional measures forroads which are not suitable for traditional trafficcalming. We should also encourage increased use ofspeed cameras in urban areas at sites where theycan improve road safety.

219. We should continue to encourage anddisseminate best practice in urban safetymanagement which includes main streets and

traffic management schemes as well as residentialareas. DETR’s Gloucester ‘safer city’ project willproduce guidelines in due course. We recommendconsideration of whether further demonstrationprojects should be conducted.

220. We should consider allowing repeater speedsigns on some restricted roads in exceptional cases(para 129 onwards). Local traffic authorities shouldreview whether the speed limit was appropriate inthe first place before exercising this power.

221. We should continue to develop and evaluatehome zones.

RURAL ROADS

222. On rural roads we recommend:

• developing consistent speed managementstrategies with local authorities and others;

• working towards 30 mph being the norm forvillages; and

• looking at whether ‘country lanes’ can bedefined for speed management purposes.

223. We suggest the development of advice forlocal authorities on intervention levels for ruralroads. It would help them identify areas that needtreatment and to target their resources mosteffectively (para 89).

224. In rural areas many people are concernedabout the speed of traffic, but it is unclear in someplaces precisely what the problem is or how to allaythese fears (para 140 onwards).

225. On parts of the rural network, for examplesome country lanes, lower vehicle speeds arenecessary. Lower speed limits may be appropriate,but other measures would be required to slow trafficsignificantly.

226. Drivers must be informed of changes in speedlimit along a road and of traffic managementmeasures ahead. The current signing is not alwaysacceptable in rural areas. We need more studies todevelop policies further.


34

227. We therefore recommend research toestablish:

• where changes in speed offer most benefits onthe rural road network;

• how to achieve appropriate traffic speedssensibly and effectively; and,

• what safety, economic, environmental andwider benefits might result.

228. We will monitor the work of the countrysidetraffic measures group to help develop trafficmanagement measures for rural areas that aresympathetic to the character of the area. Themeasures must also be acceptable to the localcommunity and maintain accessibility and viabilityof local businesses as well as achieve the requiredresults of reduced speed, environmental and safetyimprovements. We will keep local traffic authoritiesinformed of what we learn from this work.

229. We recommend issuing guidance on vehicleactivated signs. They have proved effective atreducing speeds at specific hazard points (para 87).

230. We should look at new ways of making ruralspeed limits clear to drivers and riders, eitherthrough education and publicity or by new signage.One model that should be investigated is usingvillage name signs to denote the boundaries of anarea speed limit as in France (see annex).

DRIVER EDUCATION AND TRAINING

231. We are reviewing our approach to drivertraining and testing. We are encouraging a morestructured approach to learning so that novicesbetter appreciate the responsibilities that comewith the skill they are acquiring. We are alsoresearching the practicalities of introducing ahazard perception test with moving images into thetheory test. It could help assess whether a driverappreciates what is a safe speed.

232. Future publicity should target specific areas aswell as generally warning drivers and others of thedangers of driving too fast.

233. We recommend looking to experienceelsewhere for ways to refine our methodology. ForEngland and Wales one example is the ‘Foolsspeed’campaign running in Scotland. The initial publicityaims to challenge drivers’ beliefs about their speedand driving ability.

234. We should look at fresh avenues to spread themessage. For example, we are already talking to theAssociation of British Insurers about the results ofthe research described in this report (para 187).

235. We recommend researching the best ways ofmaking sure motorists know what is the speed limitin force.


236. For those who refuse to modify their speedvoluntarily we should seek to change theirbehaviour through enforcement and penalties.Actions should include:

• reviewing penalties to make them moreeffective, particularly for the worst offences;

• evaluating new enforcement technology; and,

• developing a new financial system using part ofthe fine revenue to repay the operational andadministrative costs of speed cameras to thepolice, courts and local authorities.

237. Speed cameras will continue to be a way ofusing police resources to best effect. We recommend:

• more intensive use at existing sites;

• more cameras at new sites with either a historyof speed related collisions, or where there is aknown speed related problem; and,

• reducing trigger speeds to those in theguidelines issued by ACPO and the LordAdvocate.

238. A pilot scheme starting in April 2000 will betesting a new funding mechanism to allow finerevenue to be used to cover costs of speed cameraoperation (para 78).

Recommendations

35

239. With the exception of traffic management,speed cameras will should be used only where therewould be road safety benefits.

240. Bans for speeding are often seen as short, andfines low compared with some other offences.Magistrates in England and Wales have guidelineson how to assess appropriate penalties. Incollaboration with the Home Office and otherdepartments, we recommend continued dialoguewith the Magistrates’ Association to keep up-to-date with their sentencing for speeding offences.

241. The Home Office is leading an urgent reviewof penalties for road traffic offences. This willdetermine the best way to make penalties forspeeding more effective (see para 196). Forexample, the higher level of offence of speeding onmotorways (para 82) does not reflect the relativedanger. So there appears to be a case for increasingthe maximum penalties on other roads to the samelevel. This will send a clear message of theseriousness with which the offence is viewed.

242. The Home Office review will also addresshow to punish people who drive far in excess of thespeed limit. One option is to create a new offence.The review will also look at the penalty pointssystem and whether persistent offenders could bedeterred by the threat of losing their licence.

243. There are other ways the criminal justicesystem can educate offenders and deter speedingrather than just punishing after the event. Thesuccess of rehabilitation courses for drink drivers,and of pilot driver improvement schemes (seeannex) suggests that a similar approach might workfor habitual speeders and people who lose theirlicence for speeding. We should investigate thefeasibility of schemes, possibly linked to a re-testbefore the licence is returned.

LONGER TERM MEASURES

244. The UK is in the forefront of developingtechnology for adaptive speed limiters (para 99).We recommend participating in Europeandiscussions to maintain our position and toinfluence the development of policy. We shouldlook to develop a standard with our European

partners. We should also aim to refine the systemwith a view to introducing it in the longer term.We will need to study the legal and administrativebarriers to be overcome.

245. While engineers develop and refine thesystem and, internationally, we discuss thenecessary changes to vehicle standards with motormanufacturers, we recommend public debate withmotoring organisations about the costs andbenefits.

A NEW APPRAISAL FRAMEWORK

246. Appraisal identifies the main effects of apolicy or investment proposal on the overallobjectives for transport policy, including safety, theeconomy, the environment, accessibility andcontribution to better integration. The ScottishExecutive has recently published the results of itsstrategic roads review along with details of itsapproach to appraisal. In England a new approachto appraisal was drawn up and used to select thoseroad schemes to take forward as part of the 1998roads review. We have since made somemodifications to the way the results are presentedto assist appraisal of public transport schemes andmeasures which affect cycling and walking. Thisframework will allow DETR and local authorities toassess the full implications of speed managementschemes.

247. We need further research to identify theeffects of many of the options for speedmanagement described in this paper. Theconsequences of any proposal for safety, local airquality, journey times, emissions, noise, health andquality of life will differ according to localcircumstances. We should provide advice on howto estimate these impacts and compare differentoptions for managing vehicle speeds. It will helpdecision makers reach a well-founded conclusionon which options they should choose.

CHAPTER 5

References

36


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TECHNICAL ANNEX

Speed Policy Review

Technical Annex

3

TECHNICAL ANNEX

CONTENTS

(Subjects listed in order of appearance in the main paper.).

TERMS USED IN THE MAIN PAPER 5

NATIONAL AND VEHICLE SPEED LIMITS 5

ACCIDENT FREQUENCY AND THE PROPORTION OF 6DRIVERS EXCEEDING THE SPEED LIMIT

ACCIDENT FREQUENCY AND MEAN EXCESS SPEED 7

THE RELATIONSHIP BETWEEN ACCIDENT INVOLVEMENT 7AND SPEED CHOICE

THE MANCHESTER DRIVER BEHAVIOUR QUESTIONNAIRE 8

PROBABILITY OF INJURY RELATED TO IMPACT SEVERITY 9

IMPACT SPEED AND SEVERITY OF INJURY TO PEDESTRIANS 10

SPEED AND INJURY SEVERITY 11

AIR POLLUTANT AND NOISE EMISSIONS 11

UK SPEED LIMIT SIGNS 13

CONTROLLED MOTORWAY PROJECT 13

THE CRIME AND DISORDER ACT 13

FRENCH VILLAGE SPEED LIMITS AND SIGNS 14

REHABILITATION COURSES 14

5

Techncial Annex

Terms used in the mainpaperThe terms excessive and inappropriate speed areused throughout this paper. Excessive refers tospeeds above the mandatory limit (speeding).Drivers travelling at inappropriate speeds are thosethat whilst within the speed limit are going too fastfor conditions such as negotiating a sharp bend,during poor weather or where there are unprotectedroad users.

The distinction between these two definitions isparticularly important, regardless of whether it isroad safety or environmental issues that are beingconsidered. Establishing the nature of the problem inany given area is the key to identifying appropriatemeasures to tackle it. For example, the use of lowerspeed limits, even if they were to be respected, maynot be the best way to address all problems.

The term 85th percentile, which is used whendiscussing vehicle speeds on individual roads, refersto the speed up to which 85 percent of the traffic istravelling. Viewed another way it is the speed only15 percent of drivers exceed.

Local Traffic Authority (LTA) refers to the bodyresponsible for setting local speed limits. Generallythe LTA for trunk roads and motorways is the

DETR’s Highways Agency, and the LTA for allother roads is the local authority. In Scotland andWales responsibility for motorways and trunk roadsrests respectively with Scottish Ministers in thedevolved administration and the Weslh Assembly.

National and vehiclespeed limitsIf the local traffic authority has not imposed itsown limit on a road a national speed limit applies.The national 30mph limit is normally associatedwith urban areas and applies to all roads in Englandand Wales with street lighting, and in Scotland toall Class C and unclassified roads with streetlighting. The link between a pre-determined speedlimit and street lighting was introduced in theRoad Traffic Act 1934. These roads are called“Restricted Roads”

The 70mph limit for motorways was originallyintroduced in 1965 and re-introduced in 1977 afterthe fuel crisis, along with the same limit for dualcarriageways. The national speed limit on all otherroads is 60mph. However, lower speed limits canapply to certain classes of vehicle, and it is theresponsibility of drivers to be familiar with thenational speed limits that apply to their vehicle.Figure A1 shows the main categories.

Figure A1: National speed limits for the main classes of vehicle on roads in the UK. Source –

The Highway Code, DETR 1999c


6

Accident frequency andthe proportion of driversexceeding the speed limitFigure A2 (Taylor et al 2000, fig 11) showspredicted accident frequencies at different levels ofnon-compliance (P) with the speed limit forLondon and elsewhere (at the mean observedvalues for other variables in the model, includingexcess speed. Where Speed limit (S)=30/40 mile/h;Daily traffic flow (Q)=11/9k (London/non-L);Number minor junctions (NJ)=6; Pedestrianactivity (Peds)<200/hr; Mean excess speed (Vex)=4.5 miles/h; percentage of large vehicle in the flow(HGV)<12.5%; road class (non-B road)). InLondon the non-compliance level ranged from 4%to 73% and outside London the range was from 2%to 82%.

Figure A2

The practical consequences of influencing theproportion of speeders may be illustrated as follows.If the proportion of speeders were to increase by atenth, for example from 20% to 22%, the accidentfrequency would be expected to increase by 1.4%, ifall else is held constant. If, on the other hand, thenon-compliance level could be halved from 20% to10%, for example by increased or more effectiveenforcement of the speed limit, then the accidentfrequency could be reduced by about 10% (Tayloret al 2000).

2.0

1.8

1.6

1.4

1.2

1.0

0.8

Acc

iden

t fre

quen

cy

(per

link

per

yea

r)

Proportion of drivers (%) exceeding speed limit

[S = 30/40 miles/h; Flow = 11000/9000 (London/non-London); NJ = 6; Peds<200/h; Vex = 4.5 miles/h;

Large vehicles<12.5%; Non-B Road]

0 20 40 60 80 100

Non-London

London

7

Accident frequency andmean excess speedFigure A3 (Taylor et al 2000, fig 12) shows thepredicted accident frequency plotted againstvarious values of the excess speed for links insideand outside London (with the mean observedvalues of other variables in the model as above; theproportion of speeders is held constant for eachcurve at 25% (London) and 30% non-London).

Figure A3

The implication of the findings illustrated by thesecurves is that targeting excessive speed through theuse of measures which reduce the speed of thefastest drivers may well bring greater benefits thanattempts to influence the speed of all drivers.

The relationship betweenaccident involvement andspeed choiceResults from studies of the responses of 5000 driversto a questionnaire about accident involvement andspeed choice indicate that for an individual whodrives at a speed more than about 10-15 percentabove the average speed of the traffic around them,the likelihood of their being involved in anaccident increases significantly (Maycock et al1998, Quimby et al 1999a, b).

3.5

3.0

2.5

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Mean excess speed (Vex) of drivers exceeding speed limit

2 3 4 5 6 7 8 9

Non-London

London

[S = 30/40 miles/h; Flow = 11000/9000 (London/non-London); NJ = 6; Peds<200/h; P(%) = 25/30 (London/non-London);

Large vehicles<12.5%; Non-B Road]


8

Figure A4 (Taylor et al 2000, fig. 4) shows therelative accident involvement of a driver comparedto that of a driver travelling at the average speed(i.e. one with a relative speed of 1.0). It showsclearly that drivers who habitually travel fasterthan average are involved in more accidents in ayear’s driving.

Figure A4

The Manchester DriverBehaviour QuestionnaireResearchers at the Driver Behaviour Research Unitat the University of Manchester have developed,over time, a self completion questionnaire fordrivers from which a three fold typology of aberrantdriving behaviours have been identified. These are:

• lapses – absent minded behaviours withconsequences for the perpetrator but pose nothreat to other road users:

• errors – typically misjudgements and failures of observation that may be hazardous to others:and

• violations – deliberate contraventions of safedriving practices.

Accident liability was predicted by self reportedtendency to commit violations but not by tendencyto make errors and lapses (Parker et al 1995).

0

2

4

6

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12

0.8 0.9 1 1.1 1.2

Rel

ativ

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cide

nt fr

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g at

a r

elat

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d of

1.0

)

Relative speed (compared to a driver travelling at the mean traffic speed)

Maycock et al (1998)

Quimby et al (1999)

9

Probability of injuryrelated to impact severityFigure A5 shows the probability of injury related toimpact severity for belted front seat occupants infrontal impacts. Lower impact speeds greatly reducethe risk and severity of injury and the greatestreductions in probability are seen at the lowerimpact severities. At 30mph the risk of seriousinjury (MAIS>3) to a belted car occupant in afront seat is three times greater than at 20mph, andat 40mph the risk is five times greater than at20mph (Hobbs and Mills 1984).

Item Type

Attempt to drive away from traffic lights in third gear Lapse

Become impatient with a slow driver in an outer lane and overtake on the inside Violation

Drive especially close to the car in front as a signal to its driver to go faster or get out of the way Violation

Forget where you left your car in the car park Lapse

Underestimate the speed of an oncoming vehicle when overtaking Error

Attempt to overtake someone you hadn’t noticed signalling to turn right Error

Cross a junction when the lights had already turned red against you Violation

Hit something when reversing you had not seen Lapse

Get involved in unofficial races with other drivers Violation

Figure A5: Probability of injury related to impact severity for belted front seat occupants in

frontal impacts (based on Hobbs and Mills 1984)

0

20

40

60

80

100

MAIS>3

MAIS >2

MAIS>1

50403020100

Pro

bab

ility

of

inju

ry %

Velocity change (mph)

Respondents were required to indicate on a 6 point scale how often they indulged in each of 24 behaviourswhilst driving. Typical items on the Driver Behaviour Questionnaire (DBQ) are:


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Impact speed and severityof injury to pedestriansAshton and Mackay (1979) calculated impactspeed distributions from at-the-scene pedestrianaccidents for car and car derivatives. They foundthat 5 percent of fatalities occurred at impactspeeds below 20mph, 45 percent occurred at lessthan 30mph and 85 percent occurred at speedsbelow 40mph. About 40 percent of pedestrians whoare struck at speeds below 20mph sustain non-minor injuries however, this rises to 90 percent atspeeds up to 30mph. These distributions are shownin Figure A6 and are for the whole population. Ageeffects mean that elderly pedestrians are more likelyto sustain non-minor injuries than younger peoplein the same impact conditions.

Figure A6: Impact speed and severity of injury. Based on Ashton and Mackay (1979)

The definition of injury categories used by Hobbsand Mills was based on the 1980 revision of theAbbreviated Injury Scale (AIS) where:

The Maximum AIS (MAIS) is the highest singleAIS code for a victim

IS0 Uninjured

AIS 1 Minor

AIS 2 Moderate

AIS 3 Serious

AIS 4 Severe

AIS 5 Critical

AAIS 6 Maximum, virtually unsurvivable

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An Australian study found that in a 60km/h speedlimit area, the risk of involvement in a casualtycrash doubles with each 5km/h increase intravelling speed above 60km/h. They calculatedrelative risks of driving above the speed limitcompared with driving with an illegal bloodalcohol concentration. Even travelling at 5km/habove the 60 km/h speed limit increases the risk ofcrash involvement as much as driving with a bloodalcohol concentration of 0.05 (Kloeden et al 1997).

Air pollutant and noiseemissionsThe Environment Act 1995 requires localauthorities to review and assess the air quality intheir areas against the objectives set out in the1997 Air Quality Regulations. Road transport isone of the major sources of local air pollution and

at the national level accounts for two-thirds of allemissions of four of the eight pollutants for whichobjectives have been set by the National AirQuality Strategy. In urban areas the contribution ofroad transport to emissions can be considerablyhigher. In London, for example, around three-quarters of all particulate and oxides of nitrogenemissions are from road transport. The applicationof suitable traffic management schemes has beensuggested as a means of improving air quality inurban areas.

DETR is assessing the impacts of different speedson levels of polluting emissions. Different speedsare associated with different levels of emissions,although the relationship is not a linear one. Theeffects of speed on emissions and noise onindividual stretches of road are easier to assess thanthe effects over the network as a whole.

Speed and injury severityA Swedish model has been developed based onexperiments with different speed limits in Swedenduring 1968-71 and validated using later data. Themodel is based on the hypothesis that theprobability of an injury accident reported to the

Figure A7: Relative risk and speed. Based upon the work of Andersson and Nilsson (1997)

police is proportional to the square of the speed,the probability of a fatal or serious accident isproportional to the cube of the speed and theprobability of a fatal accident is related to thefourth power of speed (Andersson and Nilsson1997).

-60

-40

-20

0

20

40

60

80

Fatal

KSI

All

151050-5-10-15

Percentage change in speed

Per

cent

age

chan

ge

in a

ccid

ent

risk


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Figure A8: PM10 emissions from a Euro II diesel car relative to vehicle speed

Figure A9: CO emissions from a Euro II petrol car relative to vehicle speed

0

1

2

3

4

5

6

7

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130

Speed (km/h)

CO

em

issi

ons

(g/k

m)

0

0.01

0.02

0.03

0.04

0.05

0.06

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130

Speed (km/h)

PM

10 e

mis

sio

ns (g

/km

)The environmental impacts of speedmanagement measures in terms of noise andemissions are not linear or straightforward andchanges in speed have different effects ondifferent pollutants and noise levels. Duringtransitional periods, particularly during harsh

acceleration, emissions from vehicles increasesharply. To further complicate strategies to reduceemissions, production of oxides of nitrogen follows a different pattern from those of carbon monoxide or hydrocarbons.

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UK Speed Limit Signs

police with other key agencies and the communityto work together in partnership at district level todevelop and implement strategies for reducingcrime and disorder in the area. This work is toinclude conducting an audit of local crime anddisorder problems, involving full consultation;developing a strategy with targets based on thefindings of the audit; and publishing details locallyof the entire process, including ownership of thetargets and performance against them.

Home Office guidance on how local agenciesshould bring the requirements of the Act intooperation states quite clearly that the strategiesdeveloped to counter crime and disorder must bedriven by what matters to local people, and notconstrained by prerequisites or artificial definitionsimposed by central government. It goes on to say:

“so if your audit finds that, say, speeding inresidential areas is a serious matter of localconcern, then it would be just as much inorder for the strategy to focus on this issue asit would be for it to look at, for example, kerbcrawling or bogus officials in the same area.”

Controlled MotorwayProjectThe Controlled Motorway Project is currentlybeing assessed by the Highways Agency on a part ofthe M25. This automatically adjusts the speed limitto reflect prevailing conditions, and enforces itwith speed cameras. Early results have beenencouraging. Speed limit compliance has been veryhigh, the incidence of excessive speed reduced, andshort headways have been reduced.

It is too early to draw any conclusions on the effectof the system on accident rates, but lessons learntfrom the pilot scheme could possibly be applied toother parts of the motorway network.

The Crime and DisorderActSections 5-7 and 17 of the Crime and Disorder Act1998 (The Act) require local authorities and the

Prescribed Speed Limit Signs

Maximum Speed signNational Speed Limit

applies sign20mph Zone sign


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The Crime and Disorder Act does not apply inScotland where a non-statutory approach has beentaken. In determining local priorities forcommunity safety measures, including road safety, itis expected that the strategy document “SaferCommunities through Partnerships – a Strategy forAction”, drawn up by the Scottish Office inpartnership with the Association of Chief PoliceOfficers in Scotland and the Convention ofScottish Local Authorities, will have an importantrole to play.

It is too soon to establish the extent of the Act’scontribution to speed management. However, oncethe system has bedded down and information isavailable an assessment will need to be made of itseffects.

French Village SpeedLimits and signsIn France there is a national speed limit throughurban areas (agglomeration) where the size of theurban area encompasses the British definition of avillage as well as towns and cities. However, if thesettlement consists of a few houses and a garage orrestaurant it may be called a “lieu dit” in France.These settlements may have a name but they areconsidered too small to have the national urbanspeed limit applying to them and thus have thenational rural speed limit of 90 km/h. They aredenoted by a sign with the “village” name in whiteon a blue background (French sign E31). There isan expectation that drivers will reduce their speed,but this sign does not legally signify a speed limit.

For villages with more than a very small number ofhouses, the French have a sign which is placed atall the entrances to the urban area. It has thevillage or town name in black on a whitebackground and the sign has a red border (signEB10). The end sign is the name of the village inblack on a white background with no red borderbut the town name has a red line though it (signEB20). Between these entrance and exit signs thespeed limit of 50km/h applies to all roads.

Other speed limits can apply but the road layoutand required signing are specific to these limits, forexample a “zone 30” which has a 30 km/h speedlimit.

Rehabilitation courses anddriver improvementschemesThe 1991 Road Traffic Act provided for a large-scale experiment in the use of rehabilitationcourses for drink-drive offenders. Designated courtsare able to offer offenders, who they believe maybenefit, the opportunity of attending arehabilitation course run by an organiser approvedby the Secretary of State. It is for the offender todecide whether to accept the offer of a referral to acourse. The offender is required to pay a fee toattend, but, if the course is successfully completed,the period of disqualification from driving isreduced by up to a quarter.

The results from the experiment have beenencouraging. Research to date shows that in 30 months after sentencing those who hadattended a course were up to 3 times less likely tore-offend than those who had not attended. Peoplein the 30-40 age group responded particularly wellto courses. This approach may be of benefit ifapplied to speed management.

There are already Driver Improvement Schemes(DIS) run by Police and Local Authorities forspeeding offenders without reference to the courts.There may be benefit in investigating the feasibilityof developing DIS and drink-drive stylerehabilitation courses for speeding.

New Directions in Speed Management · New Directions in Speed Management – A Review of Policy 8...

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