Motorway crash makes 80 mph look foolhardy

The plan to raise motorway speed limits to 80 mph, launched to much acclaim at the Conservative Party Conference, does not look like such clever politics following the M5 disaster in Somerset and last week’s release of figures showing road deaths rising for the first time in five years.

Although there is no evidence that speed was the main cause of Friday’s disaster, reports from witnesses that they saw cars ploughing into the wreckage at 70 mph suggests that had the vehicles being going faster, the death toll could have been higher.  Moreover, almost by definition, had the following cars being going slower, they would have had a better chance of avoiding the crashed vehicles.

The accident will rightly result in closer scrutiny of the 80 mph plan announced at last month’s Manchester conference by the then Transport Secretary Philip Hammond, and therefore expose, for the first time, the shaky foundations on which the idea is based. Mr Hammond argued not only that the move was sensible given that today’s cars are far safer than 40 years ago when the present limit was first imposed, but also that it would put Britain ‘in the economic fast lane’.  He suggested it would deliver ‘hundreds of millions of pounds of net economic benefits’ as a result of saving motorists about four minutes in every hour they spend on motorways.

Mr Hammond claimed Hammthis was demonstrated by ‘research’ but he failed to put it into context. The Department for Transport later explained to me that he was using evidence published in a document entitled “An evaluation of options for road safety beyond 2010” which was undertaken for the previous government by the highly respected Transport Research Laboratory.

However, Mr Hammond did not mention two key caveats in the report. First, the change would cause an extra 18 deaths, 64 serious injuries and 363 minor ones annually as a result of the increase in the severity of accidents. Secondly, in order to prevent motorists speeding,  the researchers stipulated a dramatic rise in the installation of speed cameras. They said that average speed cameras would need to be ‘installed throughout the motorway network with necessary infrastructure to process offence data’. In all that would require 800 new camera systems – not just individual cameras – being installed on the 2,173 mile motorway network at a cost of £140,000 per system with a further  £12,000 annually each for  maintenance.

Such a wholesale introduction of speed cameras runs counter to current government thinking. In one of his first moves as Transport Secretary, Mr Hammond cut funding for local authority speed cameras and suggested that many ‘have been used abusively in some places just to collect revenue’.  Removing them was a key part of his policy of ending what he called Labour’s ‘war on the motorist’.

However, installing cameras is seen as an integral part of the scheme by the researchers because otherwise the increase in the death toll on the roads would be higher and would consequently wipe out much of the economic benefits of the change. The number of extra deaths is not stated but enforcing existing limits, they say, would save 37 lives per year.

The economic assessment of the change is calculated using the standard cost benefit methodology for transport schemes which values small time savings by motorists as an economic benefit. On the other side, deaths are valued at £1.6m each in the methodology and serious injury, at £185,000. Any significant rise would therefore greatly reduce the net benefits.

Moreover, the researchers made the calculation of the time savings on the basis that currently all motorists currently drive within the legal limit. This is an unlikely assumption and suggests the benefits might in reality be much less than implied by Mr Hammond.  As a result of the projected increase in deaths, the researchers rejected the scheme to increase the limit to 80 mph and suggested instead more road safety schemes.

Coming in the very week that figures were published showing deaths on the road rising for the first time in five years, the M5 disaster could not have come at a worse time for supporters of the 80 mph limit. Reasons for the decline range from technology such as air bags and better crashworthiness, to better enforcement of drink drive laws and the installation of speed cameras but It is clear that continuing to cut the toll requires concerted efforts rather than putting forward policies that would lead to more deaths. The simple announcement of the 80 mph plan sent a subliminal message that speeding is acceptable and that may be reflected in future numbers.

Mr Hammond has left his replacement, Justine Greening, with a dilemma: either ignore the evidence and plough on with a populist policy or perform a U-turn. If her political antennae are tuned in properly, she may decide that while ending the war on the motorist is a good sound bite, saving their lives is more important.

  • Nick

    Interesting article Christian. But do you know your website advertises supercar driving?  bit ironic!  nick 

  • Banksider33

    Usual drivel from a cyclist. And to quote: “Although there is no evidence that speed was the main cause of Friday’s disaster…”

    No there is no evidence but the it would be a balance piece of drivel if you mentioned the smoke.
    And, as I am a motorist, why is it OK for an 81mph speed limit on most Euro motorways but not here. 
    Get a car and drive, then you can comment objectively. 

  • Banksider33

    Usual drivel from a cyclist. And to quote: “Although there is no evidence that speed was the main cause of Friday’s disaster…”

    No there is no evidence but the it would be a balance piece of drivel if you mentioned the smoke.
    And, as I am a motorist, why is it OK for an 81mph speed limit on most Euro motorways but not here. 
    Get a car and drive, then you can comment objectively. 

  • Christian Wolmar

    What on earth makes you think that just because I’m a cyclist, I don’t drive? Of course speed contributed to the disaster. Yes, the smoke may have been the primary cause, but if people had not being going too fast to stop within their sight lines, they would not have smashed into the wreckage. Simples. Read what I wrote.

  • Paul Holt

    The article has missed the target.   It is not maximum speeds but minimum speeds that are the problem.   It is jams and bottlenecks that CW needs to concentrate on; clearing those allows traffic to flow and the higher speeds needed to make up time after hold-ups will no longer be needed.

  • Paul Holt

    CW: “…if people had not being going too fast to stop within their sight lines, they would not have smashed into the wreckage.”

    Quite right, which makes the maximum speed discussion irrelevant.   People should always travel at a speed at which they can stop in their sight line, which makes the accident ultimately driver error.

  • stimarco

    “Of course speed contributed to the disaster.”

    The initial incident that triggered the M5 pile-up appears to have been heavy smoke from a nearby bonfire drifting across the motorway, affecting visibility. What caused the subsequent pile-up itself was the fact that these are cars, which are currently still driven entirely by fallible human beings. These drivers clearly failed to drive properly.

    As others have pointed out: the speed limit isn’t an *order to drive at that speed*. It’s a *guide*. The Highway Code *explicitly* states that you are expected to drive at a speed _suitable to the prevailing conditions_. If there’s a lot of cloud or smoke, you’re supposed to slow the hell down, not plough on through it in the hope that you won’t hit anything! 

    This accident—as with most such accidents—was most likely driver error, not a design fault of the infrastructure.

    Speed contributes to *all* crashes, practically by definition. Would you argue for a blanket reduction of speeds on the rail network too on the same grounds that the *potential* for deaths and injuries would be reduced? No? Then you, sir, are a hypocrite.

  • Len

    Although the legal speed limit on much of the network is 70mph, it is mainly enforced at +10% +3mph – i.e. 80 mph. It would be better to accept the 80mph and enforce it with average speed cameras. Of course unregistered vehicles, particularly those bearing cloned and foreign plates (I doubt that many foreign registered cars are still run by their foreign owners) can contine to ignore cameras.

    I would also suggest that lower limits be applied for poor conditions, as in France.

    The present limit rules for different types of vehicles also need looking at. Trailers, large good vehicles, car derived vans and other vans can all have different limits on the same road.

    Finally, car speedometers should all be properly calibrated. Some read up to 10% less than actual speed.

  • Why mess with something that isn’t broken?? The lower limits in poor conditions would be a far beneficial way to go.

  • stimarco


    Given the rush to fit AWS to trains in the interests of safety, could a similar case be made for compulsory radar / laser detectors and automatic braking systems for cars? If not, why not?

  • Startearlysavestress

    None of us, including drivers, can ignore the boring but unescapable laws of physics. The kinetic energy that has to be destroyed when a car needs to stop increases with the square of the speed. So a car travelling at 80mph has 31% more destructive capacity than one travelling at 70 mph. Whereas the speed (and theoretical time saving) has only increased by 14%. For the same vehicle, the faster it is travelling, the shorter the time available to stop in a given space. Add to that the fact that the faster a car travels, the greater space is needed for a driver to react and apply the brakes. So, increase the speed, and the likelihood of a collision increases together with the severity of that collision. The average car has got heavier, which also increases its energy proportionately. Higher speeds cause more deaths and injuries, no argument. Many drivers ignore the current speed limit (well they do on the M3 anyway!). I suspect that there were drivers exceeding the speed limit at the M5 crash. It’s unlikely we’ll ever know for sure, but normal motorway behaviour suggests that it was almost certainly the case.

    Yes, it was probably caused by smoke, but the unexpected will always happen, and higher speeds significantly reduce the drivers’ capability to avoid the consequences of such a problem. They also increase the destructive energy available to cause death, injury and damage.

    Most of the traffic jams I have ever experienced on motorways have been caused by speed, in that cars are meeting up with a wave of slow moving vehicles, because the road cannot cope with the number of vehicles travelling at high speed. So, the traffic automatically compensates by enforcing a period of crawling to get the average speed down to one where the road can actually cope. Hence the variable speed limits on the M25. I live near enough to the M3 to get the full roar when the wind is in the South. Speed advocates; please remember that more speed means more noise, and there are millions of us living close enough to suffer it.

    I would mention the CO2 issues of speed too, if I thought it would be taken seriously. Every mph created is done by extra fuel consumption, and that energy has to be totally destroyed to bring the car to a halt (unless you have regenerative braking, which I guess is unfashionable amongst petrol heads).

    Trains run at speed on a highly regulated and disciplined system, according to pre-arranged paths. If car drivers were happy to accept such limitations on their freedom, I guess the dangers of higher speeds could be compensated for. Be glad with what you have got and relax and stick to the limit!

    I’m sure that regular cyclists are hyper-aware of the risks of speed, both their own, and that of the vehicles that menace them.


  • Paul Holt

    I’m glad you’ve mentioned CO2, but the point is that it is unnecessary braking that creates most CO2.   Cars moving steadily create little CO2, it is stopping and starting which drives CO2 up (compare urban fuel consumption with motorway fuel consumption).

  • Startearlysavestress

    Absolutely right, but I’ve never got anywhere in my car without stopping at least once (at my destination). A driver who goes up to 80mph on a journey will release more CO2 than one on a similar journey who doesn’t exceed 70mph. The fuel consumption needed to gain that extra 10 mph cannot be retrieved however smoothly he drives. Higher maximum speeds on a crowded motorway will increase the tendency for stop/go as the traffic has to adjust to the road’s capacity. On my old commute, I have witnessed hundreds of cars racing at over 70mph between queues at roundabouts on a dual carriageway. Timing the journey from one exit to the next roundabout entrance showed that the road was consistently permitting an overall average speed of about 30 mph! The speeders were just  queue jumping, and their disproportionately small improvement in overall journey time was gained at the expense of a wasteful expulsion of a lot of  CO2 and noise.

  • Surely “economic benefit” of driving faster to get there sooner is off set by using loads more petrol as you go faster. This will inevitably increase as petrol gets more expensive.

  • Colin

    Both my car and motorcycle are capable of sustained running at 100mph plus.

    However, do I think 80mph is sensible for the motorways?


    Neither the increased risk of accidents or decrease in fuel economy can justify what would actually work out to be an improvement of just a few mph in average speed.

  • Paul Holt

    Two years on, the Sheppey bridge crash: Both the M5 crash and Sheppey bridge appear to have been caused by a sudden reduction in visibility, due to smoke in the former case and fog.