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Published byGodwin Philip Kelley Modified over 9 years ago
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Safe Speed presents... The truth about speed and safety
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2 This short talk Road safety is a vast and subtle subject –We’ll cover just a percent or two Current policy is based on: –… several key false assumptions - but even one of those could easily take the whole talk –… an oversimplified dogma with no proper basis in science. But we’ve “done our homework” properly and welcome any questions
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3 Introduction Speed camera fines are doubling every three years Our roads are getting more dangerous - deaths are UP Road safety policy has failed Good people are losing their livelihoods The Police public relationship is being gradually destroyed Bold changes are long overdue
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4 The law Almost all drivers exceed the speed limit from time to time When our speeding laws were conceived digital enforcement and fixed penalties were not even imagined Dangerous drivers are not identified The competent and careful actions of a majority of responsible people should obviously be considered legal
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5 A fine road safety system UK roads are the safest in the world We achieved that long before we changed policy and introduced speed cameras But we are fast losing our world lead. In fact we are now the slowest improving country in Europe. What went wrong?
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6 ‘Excessive Speed’ crashes 11% of injury crashes and 28% of fatal crashes have excessive speed recorded as a contributory factor. Are these crashes caused by otherwise responsible motorists exceeding a speed limit? No - we have to look inside the figures
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7 ‘Excessive speed’ problem 1 ‘Excessive Speed’ is defined as ‘speed inappropriate for the conditions or in excess of a speed limit’. Sample data from Avon and Somerset, Durham and Canada all suggests the same split - 70% inappropriate and 30% in excess of a speed limit. So the DfT’s 11% immediately becomes 3.3%.
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8 ‘Excessive Speed’ problem 2 The coding system in use allowed contributory factors to be recorded as ‘possible’, ‘probable’, or ‘definite’. TRL323 gave us these figures: definite 30%, probable 38%, possible 16% and confidence not recorded 16% So within our remaining 3.3%, a significant percentage weren’t excessive speed at all!
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9 ‘Excessive speed’ problem 3 Many dangerous high speed crashes are caused by people acting far outside normal responsible behaviour. Joyriders in stolen cars, unlicenced and underage drivers, drunk drivers, Police drivers in an emergency response situation, escaping criminals, motor racing on the highway and so on.
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10 What is speed? Speed is measured in miles per hour. You can’t measure danger in miles per hour unless you have fixed conditions. But there are no fixed conditions. Speed can be judged to be appropriate or inappropriate. You can’t tell if a speed is safe or appropriate if you only know it in miles per hour.
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11 Conditions Road type, road width, road surface, parked vehicles, vehicle type, presence of other road users, behaviour of other road users, dry road / wet road, driver experience, road features (bend, junction, traffic lights etc), visibility, night / day, other hazards, etc, and especially distance known to be clear.
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12 What is speed? 2 Appropriate speed and Numerical speed are very different but they are frequently confused You can drive perfectly safely for years on end without a working speedo –So how important can the number on the speedo be? You can’t measure safe driving in miles per hour
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13 The truth about speed and accidents Very few accidents are caused or contributed to by normal responsible motorists exceeding a speed limit. We estimate around 1%. Many high profile high speed crashes do not involve “normal responsible motorists” Most “excessive speed crashes” do not involve exceeding a speed limit
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14 The Supposed speed / accident relationship It’s true that if you drive “too fast” you have a greatly increased risk of crashing. A driver at exactly 30mph will soon crash if he does not adjust his speed to the conditions. A driver who properly varies his speed to take account of the conditions will not crash.
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15 Time to react It’s often claimed that reduced vehicle speeds would give more ‘time to react’ But time to react is delivered routinely and continuously by observation, anticipation and planning (OAP) OAP are core driver skills Nothing happens suddenly - unless you failed to see it coming
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16 False and misleading data Many of the modern claims in road safety are false, inaccurate or misleading in some way. Take nothing on trust! Examine claims and assumptions carefully We’ll look at two key examples...
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17 Crashes down 40% at speed camera sites It is true? Yes. Did the camera cause the reduction? No. Amazingly this is a constantly repeated deception. Frequently it is quite deliberate. How does it work?
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Regression to the mean Important! Virtually all claims of crash reductions “at camera sites” depend on this error.
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19 Pedestrian impact speed data The government and the camera partnerships frequently quote: At 40mph impact 90% die At 30mph impact 50% die At 20mph impact 10% die How do these figures fit into the real world?
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20 The Ashton Mackay graph
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21 Official figures In 2002, in built up areas (30 and 40mph limits), the following figures apply to child pedestrians: Fatalities: 58 Injuries: 13,937 Proportion of fatalities 0.42% What was the average impact speed?
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22 The Ashton Mackay graph
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23 Road user response There’s a massive gap between “expected” pedestrian fatalities and real pedestrian fatalities The gap is road user response Drivers slow in areas of danger and brake before impact Road user response is at least 500 times more important to accident outcomes than free travelling speed
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24 Accident frequency data With 32 million drivers and 214,000 injury accidents each year, the average driver goes 150 years between causing injury accidents. Much of the time, our average driver will be exceeding the speed limit. The DfT said recently that 12.5% of crashes involved “excessive speed”.
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25 Speeding and accident frequency If 1 in 8 injury accidents involve “excessive speed” then the average driver has an “excessive speed” injury accident once in 1,200 years. Speeding behaviour present every day is extremely unlikely to distinguish an event that takes place once in twelve hundred years.
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26 Road safety fundamentals Road safety isn’t primarily an issue of physics or mechanics Accidents happen when road users make mistakes Most mistakes are carelessness or inattention Road safety is mainly an issue of psychology
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27 Road safety fundamentals 2 We earned the safest roads in the World long before speed cameras We didn’t do it by accident or luck We used the right experts, asked the right questions and created the right safety culture Safety culture is the key to road safety
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29 Speed camera effects Speed cameras don’t slow us down (except at speed camera sites) But they do change the things we pay attention to And they do alter the way we think And they do alter our safety priorities We need to examine the side effects of speed cameras
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30 The Speedo How many times would you check yours?
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31 Speedo checks 30% of drivers give up more than half of their attention near a speed camera 70% of drivers give up 40% or more of their attention near a speed camera
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33 These side effects seriously undermine road safety.
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34 They have not been officially studied.
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Weapons of mass distraction
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37 What’s the answer? We need to scrap speed cameras - they are just a huge distraction - We need to identify and deal with the worst drivers We need to encourage the rest to improve We must get back to the policies (and the experts) that gave us the safest roads in the World in the first place
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38 Skills Attitudes Responsibilities Engineering Enforcement Safety culture
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39 Safe Speed Intelligent road safety http://www.safespeed.org.uk
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40 Paul Smith Founder of the Safe Speed road safety campaign More than 7,000 hours investigating and analysing the overall effects of speed cameras on UK road safety A life long interest in understanding how road accidents are avoided
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41 Safe Speed is... A serious road safety campaign A web site A leading source of road safety analysis A meeting point for advanced “system level” road safety ideas Not afraid to challenge conventional thinking
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42 Oversimplified thinking “The faster you go the harder you crash” It’s simple physics “The faster you go the less time you have to react” These views don’t describe road safety reality. Road safety isn’t physics or mechanics. It’s psychology.
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43 Examples Crash severity scales International accident comparisons UK History Crash frequency
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44 The real world Non-injury and unreported accidents x2 Near misses x5 14,000 x 2 x 5 = 140,000 incidents 59% of drivers speeding in 30mph zones at sample sites In the majority of incidents, drivers would have been speeding in good conditions before the incident
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45 And now for the proof 59% of 140,000 is 82,600 speeding drivers in incidents Ascribe all the 58 deaths to speeding drivers We have left over 82,542 drivers who would have been speeding in suitable conditions before the incident who all managed to avoid killing
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46 Speeding kills? 58 / 82,600 fatalities = 0.07% Or 99.93% of speeding drivers managed to avoid killing the child pedestrian. If 99.97% of speeding drivers didn’t kill because of their speed, what saved the children?
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47 The Risk Triangle Approximate annual figures –3,500 killed –30,000 seriously injured –300,000 slightly injured –3,000,000 damage only accidents –30,000,000 near misses You can’t create this pattern with any physics model - you need a psychological model instead
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48 Making a difference Road user response is clearly our most precious road safety asset It comes from training, attention, and importantly road safety culture. If speed enforcement dulls driver responses by a fraction of 1% the entire “benefit” of lower speeds will be swamped.
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49 Conclusions Crashes happen when road users make mistakes If we are to reduce crashes, policy must concentrate on the causes of those mistakes Road safety policy should positively address road user psychology Safety culture is the key
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50 Speed cameras Speed cameras are “bad psychology” They have dangerous side effects –drivers’ attention is diverted –drivers’ concentration is reduced –and they undermine the safety culture There is no valid basis for expecting speed cameras to improve road safety –every single claim can be easily dismissed
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52 Bad driving kills Speeding alone does not
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