Why speeding?

Infrequently asked questions: Why speeding?

I seem to spend a disproportionate amount of time arguing with speedophiles. So, why bother? They won't change their minds and neither will I.

Whoa! Back up there! Speedophiles? Isn't that a malicious attempt to paint ordinary decent folks as some kind of child molesters? No. There is a reason for using that word, and I've explained it here. I know something of how the speedophile thinks, because I am a recovering speedophile myself.

The reason I argue is that not everybody reading is a speedophile, and I don't think it's right that speedophiles should be allowed to get away with advocating a behaviour which causes danger. Speedophiles assert as if fact a number of things which are demonstrably false. Lenin once said that a lie told often enough becomes the truth, and speedophiles and their apologists seem to be engaged in a Leninist attempt to make these lies true by repeating them. But let us consider the major causes of argument:

Problem 1: Mismatched Assumptions


How dangerous is speed? The ABD'S lonely 'factoid' and the real world
From Slowdown, the newsletter of the Slower Speeds Initiative, Spring 2001

The Association of British Drivers (ABD) likes to cite a Transport Research Laboratory (TRL) report as a source for the true contribution of speed to road crashes and casualties. ABD members use the TRL report to contradict the 'mainstream' figure indicating that at least one-third of crashes are speed-related. According to the ABD, the TRL report proves that the true figure is under 5%. This is the only source of such a low figure. The ABD and a few motor lobby journalists are the only people to use it, generally to support the argument that "it is not speed but bad driving that is dangerous". The ABD especially likes to use the figure in letters to local papers where highway authorities are implementing speed control measures in response to deaths and serious injuries or local demands for safer communities. (Their preferred technique is for one or two writers to flood papers with pseudonymously penned letters to make it appear they have widespread public support.)

The Slower Speeds Initiative wrote to the Transport Research Laboratory concerning the ABD's use of the study. The TRL referred us to reports on speed. This is because the TRL study cited by the ABD, TRL Report 323, concerns "A new system for recording contributory factors in road accidents". TRL 323 is not a study of crash causation. It is a study of how to collect data. It was not designed to draw statistically reliable conclusions about the causes of road crashes. The accidents included in the three month study were not a statistically representative sample of all accidents. There is no basis for using the study to generalise about the speed-crash relationship.

The very low figure quoted by the ABD comes from a table which showed pairings of factors: In 4.04% of crashes recorded in the study, the person filling in the form paired 'excessive speed' (nowhere defined) with 'loss of control of vehicle'. 4.04% is only a subset of all speed related crashes recorded in the study. This use of statistics has been described by a professional statistician as "extremely naughty" and by the Department of the Environment, Transport and the Regions as "mischievous". DETR go on to say "it is interesting that none of the many other TRL reports on speed and accident risk have been mentioned by those using this report as the basis for their argument." The TRL 323 methodology for recording contributory factors simply does not ask the questions which would reveal the inherent dangers of speed:


 * Would the factor still have been present if the driver, and/or all the other drivers involved, had been driving more slowly?
 * IF YES, Would the factor still have resulted in a crash?
 * IF YES, Would the crash still have been so severe?

It is obvious to almost everyone (with the exception of libertarian motorists with a soap box to drive) that higher speeds reduce the amount of time any driver has to respond to the unexpected and that higher speeds increase the force of any impact. The importance of reduced speeds to crash prevention and reducing crash severity is no mystery. In fact, the TRL study beloved of the ABD and its fellow-travellers, indirectly acknowledges the overriding importance of speed:

"Virtually the only factor that road accidents have in common is that all would have been avoided if those involved had known with certainty, a few seconds in advance, that an accident was about the occur."

Lower speeds provide those few extra seconds.

Among the TRL reports the ABD does not like to cite is TRL 421, "The effects of drivers' speed on the frequency of road accidents" published in March 2000. Unlike TRL 323, this study was designed to discover the speed-crash relationship.

The authors looked at 300 sections of road, made 2 million observations of speed and got 10,000 drivers to complete questionnaires. They found that


 * the faster the traffic moves on average, the more crashes there are (and crash frequency increases approximately with the square of average traffic speed)
 * the larger the spread of speeds around the average, the more crashes there are

Significantly for the ABDs argument, and for the rest of us, they also found that:


 * drivers who choose speeds above the average on some roads tend also to do so on all roads
 * higher speed drivers are associated with a significantly greater crash involvement than are slower drivers

For these reasons they conclude that the speed of the fastest drivers (those travelling faster than the average for the road) should be reduced. The study confirmed what is described as a 'robust general rule' relating crash reductions to speed reductions: for every I mph reduction average speed, crashes are reduced by between 2-7%. More specifically, the crash reduction figure is around


 * 6% for urban roads with low average speeds
 * 4% for medium speed urban roads and lower speed rural main roads
 * 3% for higher speed urban roads and rural main roads

To put the dangerousness of speed into perspective, how many drivers care about or would notice a 2mph reduction in their average speed? Yet, averaged across the entire road network, a mere 2mph reduction in average speeds would prevent more than 200 deaths and 3,500 serious casualties a year. The authors of TRL 421 suggest that this target (about a sixth of the overall speed related casualty figure) is a 'reasonable minimum' to aim for. More importantly they use it to show "the sensitivity of accident numbers to a small change in average speed". In other words, speeds that might not seem excessive. Speeds that TRL323's methodology wouldn't even record. Thanks to Stephen Plowden, Rosamund Weatherall and DETR There are three things which inflame the argument more than any others, in my view, all due to mismatches between the underlying premises adopted by one side or the other.


 * speedophiles rail against limits because they are picturing an open road with not a car in sight, infested with Gatsos stopping them from having fun. Anti speeding campaigners picture the urban context, the road outside the local school with rat-running traffic screeching to a halt for the speed bumps and racing off again. To understand the argument one must understand both points of view.


 * speedophiles are mainly concerned about cameras. As far as they are concerned a limit doesn't exist until it's enforced (which is not a big surprise), and the major bone of contention is that suddenly they can be caught without having the opportunity to spot the enforcement activity and correct their behaviour. It's not playing the game. For anti speeding campaigners that is the whole point: for over 3,000 people in Britain last year "game over" meant a one-way trip to the morgue.


 * speedophiles (rightly) see that there is no cutoff speed above which one is safe and below which one is not. Anti speeding campaigners know that, in the words of Lennox-Boyd, then Minister for Transport, in the foreword to the 1954 edition of Road Accidents Great Britain: "Accidents arise in the main from the taking of small risks a very large number of times. A thousand-to-one chance against an accident may not be rated very high, but for every thousand people who take it there will be an accident." Risk escalates with speed, and the speed limit is the mechanism by which society communicates the acceptable level of risk to drivers.

Problem 2: "It was alright before cameras"
This is not a new problem. In 1906, Dunhill's offered their "bobby finder" driving goggles which promised to "tell a policeman from a reasonable man at a distance of half a mile." And it would be a mistake to think of the groups involved as homogeneous. While between 70% and 90% admit to speeding, most who speed are not speedophiles. Recent research shows 75% support for speed cameras, despite the increasingly hysterical posturing in the popular press and elsewhere. Most drivers accept that the speed limit is there for a good reason, even if they quibble with particular limits on particular roads. Drivers aware in advance that what they do is illegal and they risk prosecution. Many choose to break the law, in the hope that they will get away with it but, as with parking tickets, some accept their punishment with good grace and others try to pretend that what they are doing is not really a problem.

And back in 1947, JS Dean wrote: "The trouble with the facts about the law-breaking of the motorists and the motor interests is that there are too many: it is difficult even to grasp them. In fact, the position has long since passed far beyond the limits of ordinary law-breaking and become an exhibition of national degeneracy."

Problem 3: Black is White
The mental gymnastics speedophiles use take a number of forms:

Speed Doesn't Kill, Bad Driving Kills
First and biggest of the lies, this seeks to establish three things: first, that speeders and bad drivers are two separate classes; second, that the probability of crashing is not affected by speed; and third, that it is the probability of crashing which is relevant not the speed at which the crash happens.

The idea that bad drivers and speeding drivers are different is seductive. Most drivers speed, nobody wants to spend longer than they have to getting to their destination after all, and we know that only other drivers are bad. In interviews between 80% and 90% of drivers rate themselves above average skill. I would suggest that this goes right to the heart of road safety: the idea that crashes happen to other people, because they are bad drivers, not to us, because we are superior drivers. It would seem to me that the primary difference between crashing and not crashing lies not in the abilities prized by drivers themselves, such as control of vehicles at speed, but in anticipation, observation and preparation. Complacency is inherently dangerous. We are all bad drivers at least some of the time.

The idea that speeding drivers and crashing drivers are in some way separate is, in any case, flawed. A variety of studies have been conducted where drivers who crash have been asked about their history of speeding convictions. They identify a strong correlation between prior speeding (and other traffic) convictions and crash risk. A small number of dissenting studies identify no correlation and although in some cases the researchers are self-identified opponents of speed enforcement that may be a result of their conclusions rather than a cause of it. But statistics like those from the USA which show that teenage drivers in fatal accidents are 10 times more likely to have previous stops for speeding than DUI suggest that speeding is real problem. The exception to the rule is that risk of crashing is apparently reduced in the month following a traffic conviction, so arguably the best result for road safety would be to increase levels of prosecutions!

There is also a strong link between speed (as opposed to speeding) and crashing. A number of researchers have analysed the variation of crash risk with speed, and all conclude that there is a U-shaped curve of risk, with the sweet spot generally centred at or slightly below the speed limit. By the time you are travelling 15% or more above the limit your risk of crashing has at least doubled.

It is undoubtedly not true to suggest that speed and fatality are not linked. Even if speed had no influence on the probability of crashing the Joksch rule of thumb gives the probability of fatality in a crash as being related to the fourth power of average speed on the road. Speed, in short, kills.

Speeding Is Not Dangerous, Excessive Speed Is Dangerous
I've already shown that speed increases crash risk and fatality risk, but speed is not the same as speeding. One of the perennial self-justifying comments of the speedophile is that 80mph at 3am on an empty motorway is not dangerous. That is misdirection. Very few speeding convictions come from doing 80mph on an empty motorway at 3am, not least because there are very few cameras on the motorway network. In any case the often-repeated advice to ensure you can always stop well within the distance you can see to be clear very evidently applies on an empty motorway. How many times have you seen bits of shed truck tyre in the carriageway, for example? On main beam headlights, any speed much above 80mph at night is unlikely to be within the distance you can see to be clear. This is beside the point, of course. It is a rare and glorious day (or night) when we have the roads to ourselves, and at any time of day or night someone could be taking actions based on the assumption that other traffic is moving more or less according to the rules.

Here is a pertinent quote from a Usenet thread on speeding, in which someone who had already admitted the obvious fact that speeding increases risk was still trying to argue that speeding was not dangerous: "[As an] analogy, consider smoking: the consequences to health of smoking, and the risk of dying from smoking-related diseases, are well-known. Smokers put themselves at increased risk, we can agree; just as speeders increase risk both to themselves and to others. But somehow that doesn't prevent smokers from having that next fag, because that individual cigarette is most unlikely to kill them. Similarly the speedophile, who has speeded so many times in the past with no more than the odd grey hair to show for it, will still speed, because the next bend is most unlikely to have a child on the other side of it. If either individual carries on with their habit for long enough, we may predict that somebody will die an untimely death. I suspect that most smokers by now have a pretty good idea that they may well die as a result of their habit. Speeders should be equally aware that they may well die, or kill; although some will always deny it, for a variety of reasons."

Limits were set in the stone age
One justification people give for increased motorway limits is that they were introduced in the days of the Morris Minor and modern cars are much better. True enough in its way. But the human behind the wheel has not been improved: the reaction times are the same. In 1950, 32% of recorded crashes ended in death or serious injury. In 2002, with crumple zones, airbags, safety belts and pretensioners, collapsible steering columns, anti-submarining seats and soft dashboards, that has gone down to 18%. You are just over half as likely to die if you crash now as in 1950. Wouldn't you have expected that to be very much better? The combined thinking and braking distance at 70mph is 96m in the current Highway Code, 21m of which is thinking time. That's over a third of the recommended two second gap in free-flowing traffic. The two second rule amounts to a 60m headway at 70mph, while the usual rule of driving so you can stop "well within the distance you can see to be clear" would indicate at least 100m. Essentially, the improved braking performance of modern cars has already been consumed in recommended driving behaviour as a performance benefit, through reduced headway distances. But the speedophiles want to have their cake and eat it.

It was safe yesterday...
Another perennial speedophile straw man is the road which was a 60 limit and is now a 40 limit (or whatever). "Yesterday 60 was safe, today it can't be dangerous!" goes the argument. This is more misdirection, since it begs the question whether 60 was safe in the first place. If 60 was safe, then there is good evidence that 40 will be safer. And in many cases 60 patently wasn't safe - many villages were unable to get speed restrictions under old criteria, and have now been able to get 30 limits. Driving through a village with no footways, with houses, schools, churches and the like opening directly onto the road, was never safe.

Anecdotes are not a great way to discuss this issue but I think I can offer one which has some relevance. There is a stretch of the A4 near Reading which is a dual carriageway. This used to be a number 1 spot for overtaking. Over time it has been narrowed and the limit reduced to 40, all of which seemed to me at the time to be a blatant attempt to impede progress by blocking one of the few decent overtaking opportunities for miles. Recently I cycled along this road. Just inside the 40 limit, hidden behind bushes, is an entrance to a primary school. There are signs, but they are often hidden by foliage. The school has another entrance, I believe, which is the one normally used - that's irrelevant. What is relevant is that even at 40mph I failed to observe something which should have prompted me to drive very carefully indeed. The 40 limit is there because I was not alone in that. Like most limits on "fast" roads it was there because local residents had campaigned for it. So before you denounce your favourite 30 limit as arbitrary and inappropriate, have a really good look at the area.

Non-Speeding Drivers Cause Danger
Speedophiles propose a number of mechanisms by which those who choose not to speed "cause" danger. These include: spending too much time looking at the speedometer; driving at the limit even when conditions require a lower speed; forcing dangerous overtaking; overtaking dangerously (taking too long about it); being less alert. You will immediately see that some of these are actually an attempt to blame law-abiding drivers for the inappropriate reactions of those who are excessively focused on speed. This is not uncommon - speeders will stand on the Highway Code and require non-speeders to obey the rule on not delaying following traffic, in order to let them break the rules and laws regulating speed. They seem to see no irony in this.

The Concentration Game
Of the above arguments probably the most ludicrous is the idea that driving within the limit compromises your ability to stay alert, and that speeding is somehow an aid to concentration and safe driving. If you don't believe that this has been suggested then read this usenet post from Paul "safe speed" Smith. This argument is clearly drivel - if you can't stay alert at the limit then you are even more unlikely to be able to make the more rapid judgements required at higher speeds. The solution to tiredness is not to increase the danger by speeding, but to pull off the road and sleep.

Watch The Needle
Close behind is the notion that it is not possible to obey the limit without spending a disproportionate amount of time watching the speedo. This is fatuous for two reasons: first, most of the time you judge speed by the motion of the vehicle, and only occasionally do you need to glance at the speedo; and second, if it's such a difficult skill to master, how come we all manage to do it on our driving test? Of course, some of the more obsessive speedophiles use this as an example of why speeding is so good: newly qualified drivers, after all, have a bad accident record. Well, newly qualified male drivers anyway. Actually young male drivers, newly qualified or not. And this objection attributes to speeding all the benefits of experience, which seems rather ill-advised. After all, middle-aged male drivers with speeding convictions are more likely to crash than middle-aged male drivers without them (source: PACTS), so there is clearly nothing virtuous about speeding.

Some speedophiles raise the spectre of the child who runs out just as you are looking at your speedo. Yes, it could just possibly happen. Luckily if you're driving within the limit you have a better chance of avoiding them, and if you do hit them they have a better chance of surviving, than if you are speeding. But this assumes that one will be driving up to the limit in an area where there are children on the pavement. Only a speedophile would fail to slow down in such a situation.

I actually find this argument offensive, because I drive within the speed limits. The implication is that I can't possibly be a safe driver because I respect the limit. Thanks a bunch. Luckily I have Paul Ripley the safe driving expert on my side - he says (repeatedly) that the limit is a limit and should not be exceeded.

Now Look What You made Me Do
Few things illustrate the flawed reasoning of speedophiles better than the assertion, apparently seriously made, that drivers obeying the limit somehow "cause" dangerous overtaking. I shouldn't really have to point out the absurdity of this notion, but I have had to several times in the past. Any rational driver will realise that if it's not safe to overtake, you don't overtake. Only a speedophile in the terminal stages of the obsession could possibly consider a dangerous overtaking manoeuvre to be "necessary." I have no doubt that given the creativity displayed by some speedophiles a scenario could be advanced where the dangerous overtake is somehow obligatory, but it is hardly likely to describe the everyday situation of being stuck behind a Micra lout at 50 on a national speed limit road.

The Limit Is Not A Target
Speedophiles suggest that limits encourage people to drive up to the limit rather than using judgement and setting "appropriate" speeds. The speedophile case here rests partly on the assumption that drivers, most of whom admit to speeding at least some of the time, would normally be driving slower than the limit; and partly on the supposition that the best way to train drivers in safe use of speed is to let them make their own mistakes. Pardon me if I'm not at the front of the queue to share the roads with them while they learn. Both ignore the reason speed limits exist in the first place: drivers, left to their own devices, simply can't be relied on to set appropriate speeds. If they did we would not have speed limits in the first place.

Some speedophiles fall back on the old 85th Percentile criteria, ignoring the fact that the speeds set by unconstrained drivers typically take no account of other road users. I've already pointed out that most drivers overestimate their own skill, and there is also an imbalance of risk where excessive speed is concerned. Put simply, all the benefit of going fast accrues to the driver, while much of the risk is off-loaded onto others. The safer modern cars get the more this applies. The result is that most drivers' judgement of appropriate speed is too high much of the time. In an attempt to mitigate this risk, speed limits were introduced - against strenuous opposition from motorists. The AA was founded to warn of speed traps. So what evidence is there that drivers will set their speed better now than they did back then?

On the subject of evidence, where is the evidence that people drive up to the speed limit, rather than being constrained by it? I don't necessarily discount the proposition that it could happen, but my experience has been that when one accepts the speed limit as inevitable this knocks the legs out from under the whole speed imperative mindset, and suddenly taking a bit more time for a double-check at junctions doesn't seem like an imposition.

Danger: Risk Of Death
Ultimately what is dangerous is not just the act of speeding but the mindset that underlies it. If your dedication to the illusion of progress is such that you are not prepared to accept the law, where else will you be compromising safety for your transient personal convenience? The fact remains that higher speed is strongly associated with greater risk of crashing, and the probability of fatality rises roughly with the fourth power of speed. What is it that is so urgent as to make speeding an imperative? If you're in such a hurry why not just park in the cemetery and wait?