Why Councils Can't Be Trusted to Set Speed Limits

Ben Lovejoy argues that the time is long overdue for councils to lose the right to set speed limits


In a perfect world, speed limits would be unnecessary. Drivers and riders would adjust their speed to suit the conditions: forward vision, junctions, pedestrians, road-surface, weather, time of day and so on. Sadly, we have only to look at the average standard of driving on the road to see why this wouldn't work. Unless we are going to raise the standard of the driving test to something roughly equivalent to the IAM test, we must reluctantly accept the need for speed limits.

Reluctantly because speed limits are a very poor substitute for competent driving. We can all think of A-road stretches that are, in appropriate conditions, perfectly safe at speeds of around double the national limit. Conversely, we can all think of situations where even half the speed limit would be dangerous. I recently drove up a narrow residential street on a sunny bank holiday Monday. There were parked vehicles on both sides of the road, and most of the world's population of five-year-olds seemed to be playing there. I drove up the street at the maximum safe speed for the conditions -- about 10mph. There are few drivers quite so dangerous as that apparently sizeable slice of the population that drives everywhere at exactly the speed limit.

But with a proper driving test political suicide for any government, and only a tiny minority opting to take advantage of advanced training, low driving standards moderated by speed limits is probably the best we can realistically hope for.

In the days when speed limits were determined on the basis of police advice, and there was no national limit, this was reasonable. Most speed limits were sensible, being determined on the basis of forward vision, the presence of hazards and a study of accident statistics on the stretch in question.

The edge of the slippery slope

The application of a national limit was the first retrograde step. Suddenly a road which might, in good conditions, be safe at, say, 90mph became illegal at speeds in excess of 60. Respect for speed limits was reduced because we now had a vast number of speed restrictions which were quite unashamedly arbitrary. This is not to say that the reasoning behind the decision was wrong. If people were doing 120mph up the M1 in vehicles, traffic and road surfaces only safe at 70mph, then it would have perfectly appropriate to impose a 70mph speed limit on the motorway. What was not appropriate was to apply a blanket limit to every motorway and dual-carriageway in the country.

I am not necessarily arguing, either, that we would necessarily have a much higher limit on the M1 today. Tyres, suspensions and brakes are infinitely better today than when the limit was imposed, with stopping distances approaching half those shown in the Highway Code, but motorways are very much more crowded today. A limit of perhaps 80-90mph might be appropriate, but probably not much beyond that -- at least, not until the type of variable-limit technology used on the M25 is in place nationwide. At that point, we might well be able to have limits ranging from 30mph on crowded sections in the rush-hour to 130mph plus on empty straight sections at 2am.

Similarly with national limit A-roads. With some, 60mph is pretty much the safe limit; with others, twice that would often be safe. A key danger with national limits is that, with both types of road officially marked at 60mph, there is no advance warning of the difference between the two. A rider or driver who has just passed through one section of needlessly restricted stretch may well decide that the next 60mph limit is equally unnecessary and find out the hard way that while one was inappropriate, the other was very appropriate!

Incompetence & worse

Even worse, however, was putting control of speed limits into the hands of local authorities.

The first problem is that councils do not have the necessary expertise to set appropriate limits based on an objective assessment of the risks. They theoretically act on advice from the police, but in practice often fail to seek such advice in the first place or ignore it when it is offered.

The reason for this odd behavour appears to stem from a combination of arrogance -- councillers believing themselves qualified to reach judgements in areas in which they have no qualification or training, a fault not limited to matters of road safety -- and political expediency. Reduced speed limits are popular with residents along the stretch in question, earning councillers brownie-points, even if an objective study of speeds before and after the restriction would demonstrate it to be entirely ineffective or even, as we shall see later, counter-productive.

The second problem is that councils have long since forgotten their remit: to organise efficient and affordable local services for their residents. These days it seems that they see their role as changing the world, setting policies on such bizarre things as nuclear deterrence and global warming. One popular hobby-horse appears to be trying to discourage car use. This has led to a situation which would be laughable if it weren't so damaging: roads sub-committees -- the people we elect to ensure that traffic through the borough flows efficiently -- passing motions deliberately designed to cause congestion!

My own local authority has admitted to me in writing that it has a policy of not relieving congestion, and deliberately reduced 50% of a key arterial road's capacity by turning it into a bus lane used by just 12 buses an hour.

Speed limits are now being used in the same way: not to improve safety, but rather to cause congestion in the ridiculous belief that this will encourage people to use their cars less in order to, er, reduce congestion. This is not only unacceptable on the grounds of inconvenience and frustration, it is a major safety and health hazard. Increasing congestion leads to rising pollution, noise and -- most seriously of all -- accident rates.

I have three objections to unnecessarily low speed limits. First, they ignore Dept of Transport guidelines. Second, they are ineffective. Third, they are actually dangerous.

Unnecessary speed limits ignore DoT guidelines

The Department of Transport has laid down very clear guidelines on the imposition of speed limits. One part of those guidelines reflects the conclusion that "while the speed limit may apply some downward pressure on the speed of the fastest drivers, speed limits on their own do not reduce speeds significantly if they are set at a level substantially below that at which drivers would choose to drive in the absence of a limit." In other words, if the limit is too low, it will be ignored.

In consequence, the DoT recommends that any speed limit should be reflect the current average speed on the stretch. Specifically, it advises that a study be carried out to determine the "85th percentile speed of traffic", ie. the speed at or below which 85% of traffic travels. The proposed speed limit should not be more than 7mph or 20% (whichever is the greater) below that speed.

Not only do many (most?) local authorities ignore this clear advice, but many of them don't even carry out the necessary study to determine the 85th percentile speed.

Unfortunately, the DoT advice is just that: advice. Local authorities have no legal obligation to adhere to it. If you happen to see a notice advising of an intended reduction in the speed limit, you can object to it on the basis that this advice has been ignored and you will stand some prospect of success, but once the limit has been imposed there is no recourse.

Unnecessary speed limits don't work

The DoT advice is not given without reason: it has been clearly shown that inappropriately low speed limits don't work because drivers view them with contempt.

It is sometimes claimed that drivers who do 40mph in a 30mph zone would simply do 50mph if the limit were raised to 40mph, but a Department of Transport study showed that this is a myth. The study examined the effects of increasing a 30mph limit to a 40mph limit on six roads, measuring both average speeds and accident rates before and after the increase. The results were enlightening.

In most cases, average speeds remained static or decreased. Indeed, on the one road where the average speed increased (by 5mph, on the A58 in West Yorkshire), the accident rate still fell. The study suggests that drivers recognised the old limit as inappropriate and thus ignored it, often by substantial margins; the new limit was considered reasonable, with much greater adherence.

Similar studies in the States have shown the same effect: increasing the limit to a more appropriate speed increases respect for the limit, reduces average speeds and reduces accident rates.

Unnecessary speed limits are dangerous

The moral, then, is not simply that inappropriately low speed limits don't work, they are actually counter-productive. Further, since it is not only average speeds but accident rates which increase when these limits are applied, they are actively dangerous.

Indeed, at least one coroner has gone so far as to cite an inappropriately low speed limit as a contributory factor in a road accident death. In giving his verdict on the death of Frank Gray, the cornoner, Bill Walrond of Bury St Edmonds, West Suffolk, observed that this was the third fatal accident to occur in the short space of time since a reduction in the speed limit and commented:

"Unnecessary speed limits are detrimental to safety for various reasons. They reduce the opportunity to overtake, thereby making drivers try harder at other times; they cause traffic to bunch; they cause frayed tempers; they cause delay which makes drivers try harder at other times to make up time that they have lost. Another unfortunate effect that they have is that each unnecessary speed limit leads drivers to think that speed limits are imposed arbitrarily and therefore makes drivers less likely to observe speed limits when they ought to. Furthermore, speed limits can lead to road rage. [...] A driver with a frayed temper is not going to drive anything like as well as a driver who is calm and relaxed. Similarly and obviously a driver suffering from road rage is a hazard. Drivers should of course concentrate on staying calm and relaxed and they are at fault if they do not do so but none of that alters the connection that there can be between an accident and an unnecessary speed limit"

The unnecessary restrictions referred to at length by the coroner in the full verdict are far from an isolated case. Local and county councils across the country are gradually imposing more and more inappropriately low speed limits. National limits become 50s and 40s, 40s become 30s. The perfectly proper 30mph zones through villages gradually creep further and further out of the village either side until they meet in the middle.

Time for urgent change

Unnecessary speed limits cause frustration and delay; they don't work; and they are dangerous. Local authorities have demonstrated themselves to be incapable of setting limits appropriately. It is long past time that we passed control back to the police.

Every speed limit, existing or proposed, should then have to be justified with objective evidence demonstrating that it is, or will be:

  • justified by a proven/able reduction in accident rates
  • effective (ie. adhered to)
  • in compliance with DoT guidelines

Failing that, it should be illegal to impose or maintain it. And this should include national limits.


Copyright Ben Lovejoy 1998
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