Inappropriate Speed - January 2011

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Inappropriate speed contributes to around 14% of all injury collisions, 15% of crashes resulting in a serious injury and 24% of collisions which result in a death and are recorded by the police.1 This includes both 'excessive speed', when the speed limit is exceeded but also driving or riding within the speed limit when this is too fast for the conditions at the time (for example, in poor weather, poor visibility or high pedestrian activity).

In 2010, 241 people were killed in crashes involving someone exceeding the speed limit and a further 180 people died when someone was travelling too fast for the conditions.1

Drivers and riders who are travelling at inappropriate speeds are more likely to crash and their higher speed means that the crash will cause more severe injuries, to themselves and/or to other road users. Inappropriate speed also magnifies other driver errors, such as driving too close or driving when tired or distracted, multiplying the chances of these types of driving causing an accident.

Higher Speeds Cause More Accidents

Higher speeds mean that drivers have less time to identify and react to what is happening around them, and it takes longer for the vehicle to stop. It removes the driver's safety margin and turns near misses into crashes.

Around two-thirds of crashes in which people are killed or injured occur on roads with a speed limit of 30 mph or less. At 30 mph vehicles are travelling at 44 feet (about 3 car lengths) each second. One blink and the driver may fail to see the early warning brake lights; a short glance away and the movement of a child behind a parked car will be missed. Even in good conditions, the difference in stopping distance between 30 mph and 35 mph is an extra 21 feet, more than 2 car lengths.

If average speeds reduced by 1 mph, the accident rate would fall by approximately 5%.2, 3 This varies slightly according to road type, so that a 1 mph reduction in average speed would reduce accident frequency by about:

  • 6% on urban main roads and residential roads with low average speeds
  • 4% on medium speed urban roads and lower speed rural main roads
  • 3% on the higher speed urban roads and rural single carriageway main roads.

If an individual drives more than 10 - 15% above the average speed of the traffic around them, they are much more likely to be involved in an accident.

Drivers who speed are more likely to be involved in collisions. They are also more likely to commit other driving violations, such as red-light running and driving too close.

Higher Speeds Cause More Serious Injuries

Car Drivers


Car drivers are much more likely to be injured in collisions where there is a large change in their vehicle's velocity (which occurs when a vehicle is in a collision). Higher speeds lead to higher changes in velocity during the collision, and so are more likely to result in injuries or death.

The actual risk of injury in any collision is influenced by many factors, including the vehicle's speed, its design, strength and occupant protection systems, whether the occupants were wearing seat belts, the nature of the other vehicle(s) or object(s) struck, and the medical care received by the victims. However, on average, belted drivers have a 17% risk of being fatally injured when the change in velocity is 40 mph and a 60% risk when it is 50 mph, in a frontal impact. Half of drivers who were fatally injured were in an impact with a change in velocity of 34 mph or less.

Side Impacts

When cars are hit from the side, drivers are at a much greater risk: in a collision where the change in velocity is 40 mph the risk of a belted driver being killed is 85%.


Multiple studies (see Table 1 below) have shown that pedestrians are more likely to be severely or fatally injured in when hit by cars at higher speeds, and particularly when the car is travelling more than 30 mph.

The most recent analysis of the role of vehicle speed in pedestrian fatalities in Great Britain 4, found that 85% of pedestrians killed when struck by cars or car-derived vans, died in collision that occurred at impact speeds below 40mph, 45% at less than 30 mph and 5% at speeds below 20 mph.

The risk of a pedestrian who is hit by a car being killed increases slowly until impact speeds of around 30 mph. Above this speed, the risk increases rapidly, so that a pedestrian who is hit by a car travelling at between 30 mph and 40 mph is between 3.5 and 5.5 times more likely to be killed than if hit by a car travelling at below 30 mph. However, about half of pedestrian fatalities occur at impact speeds of 30 mph or below. Elderly pedestrians have a much greater risk of suffering fatal injuries than other age groups.

For car drivers, the risk of being killed in frontal collisions with another vehicle also increases with speed. The risk of a belted car driver being killed in an impact with another car is much higher in a side impact than in a frontal impact.


For pedestrians struck by the front of cars, the risk of fatality increases slowly until impact speeds of around 30 mph. Above this speed, risk increases rapidly (between 3.5 and 5.5 times from 30 mph to 40 mph).

For car drivers, the risk of being killed in frontal collisions with another vehicle also increases with speed. The risk of a belted car driver being killed in an impact with another car is much higher in a side impact than in a frontal impact.

Table 1: Pedestrian Fatality Risk 4



Number of injuries examined

Risk of fatal injury at 30mph

Increased risk of fatal injury between 30 and 40mph





5.5 times more likely



490 (excludes children under 15)


3.5 times more likely





4.5 times more likely

Who Speeds?

The DfT 2009 Speed Survey 5 showed that:

  • On 30 mph roads, 46% of car drivers exceed 30 mph and 16% exceed 35 mph
  • On 40 mph roads, one quarter (22%) of car drivers speed, and 8% go faster than 45 mph
  • On 60 mph roads, 8% of drivers speed but only 1% go over 70 mph
  • On 70 mph dual carriageways, almost half of car drivers (42%) exceed the speed limit, with 10% going over 80 mph
  • On motorways, half (50%) of car drivers exceed the speed limit, with 14% going faster than 80 mph.

Recent research 6 suggests there are three types of drivers:

  • Compliant drivers who usually observe speed limits (52% of drivers)
  • Moderate speeders who occasionally exceed speed limits (33% of drivers)
  • Excessive speeders who routinely exceed speed limits (14% of drivers)

However, even the moderate speeders exceed 30 mph limits fairly regularly. Excessive speeders normally ignore the 30 mph limit, and often by a wide margin.

Types of Speed-related Crashes

A study 7 of collisions involving vehicles that were exceeding the speed limit or travelling at inappropriate speed, found:

  • Most collisions involved some loss of control of the vehicle, usually on a bend.
  • Collisions were more likely on unclassified rural roads, with excess speed being more likely on 30 mph roads, and inappropriate speed on 60 mph rural roads.
  • Male drivers under 30 years old, and especially under 21 years old, were more likely to be in speed-related collisions.
  • Drivers/riders of cars and motorcycles were more likely to be in speed-related collisions than drivers of other vehicles.
  • Drivers of older vehicles, sports cars and hatchbacks were also more likely to be in speed-related collisions, as were cars containing two or more occupants.
  • Drivers who crashed while exceeding the speed limit, were also more likely to be recorded as 'aggressive driving', 'careless, reckless or in a hurry', 'impaired by alcohol' and 'stolen vehicle', highlighting the link between excess speed and other types of risk-taking behaviour.
  • Drivers who crashed while travelling at inappropriate speed, are also more likely to be recorded as 'careless, reckless or in a hurry', 'vision affected by road layout', 'vision affected by rain, sleet, snow or fog' and 'slippery road (due to weather)'.
  • In the majority of cases, the vehicle in question was travelling too fast around a bend and swung wide or lost control. Other reasons included vehicles travelling around blind bends, or following other vehicles too closely.

How Can Speed Related Accidents Be Reduced?

Driver Education

Education is absolutely vital in trying to change attitudes towards speeding. Those who drink and drive are seen as behaving in a dangerous, anti-social and selfish manner with little regard for the safety of other people. However, those who speed are often not regarded in this way unless they grossly exceed the speed limit. Therefore, it is essential that the dangers caused by driving at inappropriate speeds are clearly explained and demonstrated (in the way that has been done for drink-driving) to work towards a general acceptance and ownership of the problem of illegal and inappropriate speed.

It will be far easier to persuade people to drive at safer speeds if they understand and accept that driving too fast significantly increases the chances of being involved in an accident, and significantly increases the chances of that accident being serious or fatal.

Road safety publicity campaigns such as the Government's Think! Road Safety Campaign and the Scottish Government's "Foolsspeed" campaign are strongly supported by RoSPA.

Unfortunately, road safety education and publicity are often undermined in the mass media. Motor manufacturers, and their advertising companies, continue to emphasise the speed and power of their vehicles. Television motoring programmes continue to promote the thrill of speed, placing undue emphasis on performance at speed, often showing cars being raced (albeit not on the public highway). Television dramas often show characters driving at speed when speeding is not essential to the plot or the characterisation.

Motor manufacturers, national press, TV and advertisers should not glamourise speed as exciting and exhilarating nor as 'normal' behaviour. The Advertising Standards Authority has taken action on a number of occasions against car advertisements that promote speed, and this is very welcome. The ASA and other broadcast regulatory bodies could usefully review and strengthen their guidance in this respect.

RoSPA has produced "Presenting Road Safety: A Guide for the Media" 8 to help those working in the media to avoid inadvertently showing bad road user behaviour.

Driver Training

Speeding is a symptom of a more general poor attitude towards driving. One of the weaknesses of the UK's driver licensing system is that once the driving test has been passed, the driver is licensed, virtually for life, with no requirement and very little incentive to develop his/her driving skills any further. Drivers can voluntarily take further training, such as Pass Plus or courses offered by driver training providers such as RoSPA, but there is little incentive for individual drivers to do so. Only 3% of drivers take any further driving instruction after passing their test. 9 Therefore, there is a need to develop new ways of encouraging drivers to continue to develop their driving skills after the test.

RoSPA's report, "Refresher Driver Training", 10 examines the low awareness of post-test training options and motivations and deterrents for taking such training. A leaflet, "Get More From Your Driving" 11 is also available to promote refresher training.

Over the last 15 years or so in Britain, the driver training regime and the Driving Test has been enhanced in a number of ways to try to improve the safety of young drivers. The main changes have been the introduction of the Theory Test and in 2002 the Hazard Perception Test, the expansion of the practical driving test and the introduction of the Pass Plus Scheme. Proposals 12 for further major reforms to the UK's driver training and testing regime are being implemented, and the Government are promoting post-test driver training, and the concept of regular refresher training.

  • Graduated Licensing Systems also offer opportunities to provide phased driving experience for new drivers during the period when they are most at risk of being involved in an accident, and of reducing their exposure to the factors that are most dangerous to them. RoSPA would like to see a stronger commitment to researching and testing how such a system, and what particular elements, would be effective and feasible in the UK. This should be seen as part of the DSA's Safe Driving for Life Programme.

Speed awareness courses provide a good opportunity to educate drivers who have committed speeding offences. Many drivers seem to believe that their car will not do less than 35 mph. Education, training and publicity should seek to help drivers understand that they can control their vehicle sufficiently to drive within the 30 mph speed limit.

Highway Design and Engineering

Drivers' choice of speed is partly dependent on the characteristics of the road on which they are driving, and drivers' perception of what is a safe speed on a particular road will often differ to that of other road users, such as pedestrians, pedal cyclists and horse riders. Therefore, it is important that road design gives drivers the right messages about the maximum safe speed.

Ways of improving the road environment to encourage drivers to drive at appropriate speeds are discussed in "Helping Drivers Not To Speed" 13 and advice on how to avoid inadvertently exceeding the speed limit is provided in RoSPA's "Top Ten Tips To Stay Within the Limit". 14

Safer roads benefit all road users, but especially those who are most vulnerable: pedestrians, cyclists, motorcyclists, children and the elderly.

Speed management is central to road safety. A number of local authorities have already introduced comprehensive speed management strategies that have been successful in reducing casualties and average speeds. A wide range of good practice guidelines have been published by the Department for Transport, the Institute of Highways and Transportation (IHT) and RoSPA.

The measures that are most effective in reducing vehicle speeds and thereby reducing road death and injury are area-wide traffic calming schemes and 20 mph zones.

20 mph Zones

20 mph zones are areas where the speed limit has been set at 20 mph and traffic calming measures have been put in place to encourage drivers to stay within the 20 mph limit.

A review 15 of accident data in seventy-two 20 mph zones found that average mean speeds were reduced by 9 mph, from 25 mph to 16 mph in the zones. On average, for every 1 mph speed reduction, there was a 6.2% accident reduction.

All road accidents in the zones fell by 61%, and there was no evidence of accident migration onto surrounding roads. Traffic flows in the zones reduced by 27%. The effects were particularly significant for the most vulnerable road users:

  • All pedestrian accidents down by 63%
  • All cyclist accidents down by 29%
  • Motorcyclist accidents down by 73%
  • Child accidents down by 67%
  • Child pedestrian accidents down by 70%
  • Child cyclist accidents down by 48%

A Transport for London review 16 of over one hundred 20 mph zones in London also found that they were very effective in reducing road injuries to children. In the zones, speeds were reduced by 9 mph and traffic flows by about 15%. Road casualties in the zones were reduced by 45% and fatal or seriously injured casualties by 57%. Again, significant protection was provided to the most vulnerable road users:

  • Pedestrian casualties down by 40%, and pedestrians killed or seriously injured (KSI) down by 50%
  • Child pedestrian casualties down by 48% and child pedestrians KSI down by 61%
  • Cyclist casualties down by 33% and cyclist KSI down by 50%
  • Child cyclist casualties down by 59% and child cyclists KSI down by 60%
  • Car occupant casualties down by 57% car occupant KSI down by 77%
  • Child car occupant casualties down by 51% child KSI down by 47%

20 mph Limits

A more recent approach is the use of 20 mph limits over an area, but without the traffic calming measures. Road signs and markings, and education and publicity are used to encourage drivers to stay within the limit.

Portsmouth City Council is the first local authority in England to implement an extensive area-wide 20 mph Speed Limit scheme (without traffic calming) covering most (94%) of its residential roads which previously had a 30 mph speed limit. The scheme used 20 mph speed limit signs, including repeater signs, and 20 mph speed limit markings on the road. On most of the roads, the average speeds before the scheme 24 mph or were less, mostly because of narrow carriageways and on-street parking, but 20 mph signs were also put on roads with average speeds greater than 24 mph. The scheme was designed to be self-enforcing (avoiding the need for extra Police enforcement).

Overall, the number of roads with speeds of 20 mph or less increased. On roads with average speeds of 24 mph or more before the scheme was introduced, the average speed reduced by 6.3 mph. The average reduction in mean speeds on all roads was 1.3 mph.

Comparing the 3 years before the scheme and the 2 years afterwards, the number of recorded road casualties fell by 22% from 183 per year to 142 per year. During the same period casualty numbers fell nationally by about 14%. However, the number of deaths and serious injuries rose from 19 to 20 per year, although the low numbers mean this was not statistically significant.

The scheme was generally supported by residents, although most wanted to see more enforcement of the 20 mph speed limits. Levels of car travel stayed similar, whilst the level of pedestrian travel, pedal cyclist travel and public transport use increased slightly.


Roads policing is a fundamental and irreplaceable activity, which plays a key role in saving lives and minimising injury on the road. In order to do this effectively, roads policing must be given its rightful priority by the government and the Police Service, and be adequately resourced. The Police have many priorities, including tackling many forms of violent crime, all of which are extremely important. They must, therefore, allocate and prioritise their limited resources to the best possible effect. The level of death and injury caused by poor, and often illegal, behaviour on the road far exceeds the number of people killed through any other form of crime. Accordingly roads policing must be one of the top priorities.

Safety Cameras

Cameras are a very effective way of persuading drivers not to speed, and thereby reducing the number of people killed and seriously injured. An independent review 17 of more than 4,000 safety cameras over a four year period shows conclusively that cameras significantly reduce speeding and collisions, and cut deaths and serious injuries at camera sites by 42%.The review found:

Cameras Cut Speeds

  • The number of vehicles exceeding the speed limit at fixed camera sites fell by 70%. The reduction at mobile camera sites was 18%.
  • Excessive speeding (15 mph or more above the limit) fell by 91% at fixed sites and by 36% and at mobile sites.
  • Average vehicle speed across all new sites fell by 6% overall.

Cameras Save Lives

  • The number of people killed or seriously injured fell by 42% at camera sites. This means there were 1,745 fewer people being killed or seriously injured at the camera sites per year – including 100 fewer deaths per year.
  • The number of people killed and seriously injured fell by 50% at fixed sites and by 35% at mobile sites.
  • There was a 32% reduction in the number of children killed and seriously injured at camera sites.
  • The number of pedestrians killed or seriously injured fell by 29% at camera sites.

Cameras Prevent Crashes

  • There was a 22% reduction in collisions involving (fatal, serious or slight) personal injury at camera sites. This equated to 4,230 fewer personal injury collisions per year.

A review of the evidence of the effectiveness of speed cameras in 2010 18 examined data from the above four year study plus many other UK and international studies along with data on traffic speeds, collisions and casualties. Taking into account other factors that might reduce speeds, and speed-related crashes and casualties, such as the downward national trend in casualty numbers, regression to mean (as many cameras were installed at sites with untypically high numbers of casualties, casualties might have fallen back towards the average level anyway) and drivers diverting to avoid cameras, concluded that in the year ending March 2004, cameras at more than 4,000 sites across Great Britain prevented some 3,600 personal injury collisions, saving around 1,000 people from being killed or seriously injured (KSI).

The report also concluded that if safety cameras were decommissioned about 800 extra people across Great Britain could be being killed or seriously injured each year.

Vehicle Engineering

Motor manufacturers could play a much more prominent role in reducing the number of people killed and injured in speed-related road accidents. Manufacturers continue to produce cars and motorcycles that are capable of achieving speeds of 160 mph and more. RoSPA believes that the European Commission, national governments and the motor industry should work together to develop restrictions on the top speeds and power of new cars and motorcycles.

Modern cars provide a smooth, quiet drive, even at very high speeds, and therefore drivers are often insulated from any real sensation of the speed at which they are travelling. The vehicle's power means that it is very easy to creep above the speed limit. Indeed, drivers often cite this as a reason for speeding.

Intelligent Speed Adaptation

Technology which can prevent drivers from exceeding the speed limit on any particular road is being developed and tested. The latest field tests 19 show that this "is now a mature technology which is capable of delivering substantial reductions in excessive speed and thereby considerable benefits in terms of safety."

Depending on how the technology is implemented, over the 60 year period from 2010 to 2070, it would be expected to reduce fatal accidents by between 10% (approximately 15,400 fatal accidents) and 26% (approximately 43,300 fatal accidents), serious injury accidents between 6% (96,000 accidents and 21% (330,000 accidents), and slight injury accidents by between 3% (336,000 accidents and 12% (1.3 million accidents).

One of the requirements for the widespread implementation of this technology is a digital map showing the speed limit on every road in the country, which can easily and regularly be updated, including taking account of speed limit changes due to road works. Ultimately, this will make it possible to display the speed limit of every road within the car, so that a driver can constantly be aware of the limit.

Some Satellite Navigation devices can also advise drivers of the speed limit of the road, although drivers should still primarily rely on the legal road signs, in case the device is not up to date or there is a temporary limit in place.

Ways in which car manufacturers could make it easier for their customers to stay within speed limits are discussed in RoSPA's Policy Paper, "Helping Drivers Not To Speed".12


Driving is the most dangerous work activity that most people do. Around 150 people are killed or seriously injured every week in crashes involving someone who was driving, riding or otherwise using the road for work purposes.

HSE Guidelines, "Driving at Work", 20 state that "health and safety law applies to on-the-road work activities as to all work activities and the risks should be effectively managed within a health and safety system".

Employers should identify high risk drivers and high risk journeys and set schedules that are generous enough to ensure that drivers are not time-pressured into speeding. They should make it clear that they expect all employees to comply with posted speed limits when driving in the course of their work and that failure to do so will be regarded as a serious matter. They should consider the speed performance of their company vehicles, assess driver competence and provide appropriate driver training.

RoSPA has produced a Guide, "Driving for Work: Safer Speed Policy", 21 to help employers and line managers to ensure that their staff are not tempted or pressurised into driving at inappropriate speed. It includes a sample 'Safer Speed Policy' which can be adopted as written or adapted to suit an organisation's needs.


There is no doubt that inappropriate speed is one of the most serious road safety problems on Britain's roads, and causes death and injury to thousands of people each year. Unfortunately, the danger caused by speeding drivers has not yet been accepted by the public in the same way as the danger caused by drink-drivers.

A co-ordinated speed management strategy must include education, training and publicity, highway engineering and design, vehicle engineering and enforcement measures. Employers have a powerful role to play in influencing employee driver attitudes and behaviour. But ultimately, all drivers and riders need to be persuaded that driving at inappropriate speeds is not a minor, technical offence that everyone commits, but a serious, dangerous and anti-social activity.


  1. "Contributory Factors to Road Accidents", Road Casualties Great Britain 2009, DfT 2010
  2. "Contributory Factors to Reported Road Accidents", Article in "Reported Road Casualties Great Britain, 2010", Department for Transport, 2011,
  3. "Speed, Speed Limits and Accidents" Finch et al, TRL Project Report 58. TRL, 1994
  4. "The Effects of Drivers Speed on the Frequency of Road Accidents", Taylor et al, TRL Report 421, 2002
  5. "Relationship between Speed and Risk of Fatal Injury: Pedestrians and Car Occupants", Road Safety Web Publication No.16, Department for Transport, September 2010
  6. "Free Flow Vehicle Speeds In Great Britain 2010" Tables SPE0101 and SPE0102, DfT 2011
  7. "Understanding Inappropriate High Speed: A Quantitative Analysis", Road Safety Research Report 93, Stradling, DfT, 2008
  8. "The Characteristics of Speed Related Collisions", Road Safety Research Report 117, Department for Transport, Sept 2010
  9. "Presenting Road Safety: A Guide for the Media", RoSPA, 2004
  10. "Accidents Rates and Behavioural Characteristics of Novice Drivers in the TRL Cohort Study", TRL Report 293, R West, 1998
  11. "Refresher Driver Training", RoSPA, 2005
  12. "Get More From Your Driving", RoSPA, 2005
  13. "Learning To Drive: A Consultation Paper", DSA/DfT, 2008
  14. "Helping Drivers Not To Speed", RoSPA, 2007
  15. "Top Ten Tips To Stay Within the Limit", RoSPA, 2007
  16. "A Review of Traffic Calming Schemes in 20 mph Zones", TRL Report 215, 1996
  17. "Review of 20 mph Zones in London Boroughs" TfL Safety Research Report 2, 2003
  18. "The National Safety Camera Programme: Four-year Evaluation Report", University College London & PA Consulting, 2005
  19. "The Effectiveness of Speed cameras: A Review of Evidence", Prof R Allsop, RAC Foundation, November 2010
  20. "Isa- UK intelligent speed adaptation: Final Report", the University of Leeds and MIRA Ltd, June 2008
  21. "Driving at Work: Managing Work Related Road Safety" INDG 382, HSE & DfT, 2003
  22. "Driving for Work: Safer Speed Policy", MS 190, RoSPA, 2004

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