Sustainable safety – the British way

One of the principles of the Dutch approach to road safety – sustainable safety, or duurzaam veiling – is homogeneity. Homogeneity of mass, speed and direction.

Roads should be designed to eliminate, as much as possible, mixing road users with large differences in speed and mass in the same space. So, for example, relatively slow pedestrians should not have to mix with relatively fast bikes, and relatively light bicycles should not have to mix with relatively heavy buses or HGVs. Likewise road users who travel slowly should not be expected to share space with vehicles travelling considerably faster.

It appears this principle has been grasped by the Freight Transport Association, who argue

we believe there is evidence confirming that road safety will be improved if the differential between HGVs and other road users is reduced.

Sounds fantastic!

Except… the measure the FTA are welcoming involves reducing the speed differential by shifting lorries to a higher speed, so they are travelling at the same speed as smaller motor traffic.

Conveniently the FTA seem to have overlooked those ‘other road users’ who will still be travelling at around 15mph, or slower, for whom this move to higher speed limits for HGVs will distinctly worsen their safety, according to the logic that the FTA themselves accept. The speed differential between people walking, cycling and horse-riding, and HGVs, is being increased.

Sustainable safety – the British way!


The DfT press release similarly completely overlooks the effect this speed difference will have on vulnerable road users. It states –

This change will remove a 20mph difference between lorry and car speed limits.

… while adding a ~40mph speed difference between HGVs and people walking, cycling and riding horses. Great stuff guys.

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17 Responses to Sustainable safety – the British way

  1. Bez says:

    I think Edmund King’s comment—

    “We know from our members that quite often trucks doing 40mph on rural roads not only causes congestion but actually causes added danger. If the truck is doing 50mph, all the evidence suggests that the driver will be quite content to stick behind it rather than try to overtake.”

    —lacks depth. For a start, “the driver” is a nonsense phrase. What he means is that fewer drivers will overtake. Which is perfectly reasonable and entirely unsurprising.

    The problem is this: how many of the drivers who now will overtake are the ones who do so dangerously? I am reasonably confident in a hypothesis that it is the drivers who take greater risk who are likely to continue to do so, whilst those who prefer less risk will be more likely to sit behind.

    The reason I’m confident in that hypothesis is that overtaking is behaviour, and behaviour is governed by attitude to risk. This effect doesn’t seem something that requires retrospective statistical analysis to have credence; such analysis would only be required to determine the extent of the problem.

    So, this legislation may not even reduce the number of dangerous overtakes. But where overtakes occur, they may well be done passing a vehicle at greater speed, making the manoeuvre inherently *more* dangerous.

    Of course, if you just say “more people overtake vehicles when they’re going more slowly” and work on the basis of that incredibly shallow statement, then it provides a nice little way to meet the demands of hauliers for whom time is a cost but fatalities are not.

    • fonant says:

      More to the point, the idea quickly back-fires on the faster motorist when there are lorries around on single carriageway one-lane-each-way roads.

      A powerful car driven by a man with high risk requirements can relatively easily overtake a lorry doing 40mph: Accelerate swiftly to 60 mph and your passing speed is 20mph, leading to less time spent overtaking, and less distance spent on the wrong side of the road. If the lorry is travelling at 50mph, however, you need to accelerate to an illegal 70mph to overtake it in the same time, but at that speed you will need significantly more road length. If the overtaking car sticks to the legal maximum speed, it takes them twice as long to pass the lorry. In both situations it becomes much more difficult to overtake.

      So instead of fast motorists being able to overtake 40 mph lorries, they get stuck for long distances behind 50 mph lorries. I suspect the change from occasional-slow-but-exciting-overtaking to regularly-stuck-and-unable-to-overtake will prove extremely frustrating for a certain class of motorist.

      This is nothing to do with cars overtaking lorries, it’s all about reducing journey times for lorries.

      If the FTA were really wanting to homogenise things, they should look at the total kinetic energies involved. By my calculations a 44 tonne lorry doing 40mph has a kinetic energy of 7 MJ, compared to a 1.5 tonne car doing 60mph which has 0.5 MJ. Lorries up to 3 tonnes should be allowed to travel at 40mph. 44 tonne lorries should be limited to just 11 mph to have the same kinetic energy as a car doing 60 mph.

  2. pshore2 says:

    Looking at the government press release they are trying to use the get-out that local authorities can change the road-speed-limit down where appropriate. [not to be confused with the vehicle-speed-limit for a given road type]

    A few thoughts:

    * The proposal wants to increase the limit by default, then asks for local authorities to argue on a case-by-case basis which roads have been made unsafe. We know that local politics will make this a slow, piecemeal process. Begs the question, for safety’s sake why not do the reverse, putting the default road-limit *down*, then debate on which roads are safe enough to allow fast speeds?

    * Local authorities already struggle to get funding to change speed limit signs. We’ve seen this via 20mph limit changes.

    * Local authorities are not allowed to manage limits on Highways Agency Roads.

    • Stevie D says:

      If only. Local authorities have consistently shown themselves to be grossly irresponsible in reducing speed limits left, right and centre – where there is no legitimate safety concern, and at vast expense, and for little or no predicted benefit. Anything that crimps their power to do this has to be welcomed.

    • fonant says:

      A simple cost-effective solution would be to decree that all speed limit signs now display the maximum speed in km/h. So all our 30mph limits become 30 km/h limits, just as in continental Europe. Then we can make the (unsigned) motorway speed limit 120 km/h and everyone is happy because they can legally “do a ton”.

  3. Simon Still says:

    My observations from spending yesterday watching over a crane and parking suspension on a residential road. Road is used as a rat run, has a ‘speed check’ sign but is 30mph with no traffic calming despite having a youth club, a major walking route from an estate to a school and LCN 25 running on it for 100m or so just up the road.

    To get past the crane it was necessary for most vehicles to mount one wheel on the (shallow) curb. Our new neighbours called us before 8am because drivers were not slowing down and were mounting the pavement at speed despite there being pedestrians about.

    We went to site and rigged up some tape between some trestles to visually narrow the gap and set out 75% of the pavement for pedestrians. I then sat by this in reflective jacket and hard hat for the day.

    Many drivers responded to this by slowing right down, some asked permission/confirmed safe to pass but a significant minority still tried to negotiate this obstacle at speed. A staggering proportion were also on their phones (and the overlap between speed and phone use was even more alarming including a guy with phone in one hand and drink can in the other as he ‘held’ the steering wheel).

    Dangerous drivers are dangerous drivers and the Police simply do not enforce traffic laws sufficiently to ensure their licences are taken away. The worst driver yesterday we reckon went through the obstruction at over well over 30mph and accelerated hard afterwards – probably to close to 60mph (the speed check stops registering at 45mph so above that) I’m pretty sure he comes through the road at a similar time and speed every day yet the Police are uninterested. His behaviour suggests he has no fear of being penalised and if he was caught it would be treated as a single aberration whereas I’m sure he drives like that everywhere.

    • D. says:

      I watched something similar from my office window one time. A *huge* crane had been set up, the road pretty much closed leaving about three feet of road open (20 mph limit, small road in central Bristol with my office’s car park along one side of it).

      People were approaching the crane, moving over and using the dropped kerb for our car park entrance to get past; in many cases, not even slowing down, forcing pedestrians using the footpath to get out of the way.

      I ended up phoning the council – it turned out that the crane operator hadn’t had permission anyway (they had permission for half the road to be closed, but had played down quite how ginormous their crane was) and the man from the council came and closed them down, made them come back outside of office hours.

  4. Jim says:

    Is this thing a done deal now? Can we do anything about it?

    • Tim says:

      Yes, this. Will writing to my MP make any difference (especially considering he’s Labour)?

      It beggars belief that this goes under the DfT “Making Roads Safer” heading.

  5. T.Foxglove says:

    £11m benefit to the haulage industry, £1.9m cost to the economy for every road death (page 38 of govt report, so five or fewer more deaths per annum and the nation will be quids in.

    • T.Foxglove says:

      Damnation. That sentence didn’t look half as clumsy until just after I pressed ‘post comment’.

  6. Felix the cat. says:

    I fully agree that this proposal is a fundamentally bad idea.
    In practice though, it will make very little difference. The 40 mph limit is ignored in my experience. I once came across a lorry doing a legal speed but it turned out that the driver was being trained.

  7. Rachel B says:

    Yet another reason for me to avoid country A roads on longer cycling trips then… If the close passes and dangerous overtakes from cars and smaller vans aren’t enough – now there will be large HGVs going even faster. I’ve only held a driving license for the last 20 years so please excuse my ignorance – but I thought that larger vehicles were speed limited due to their greater mass and momentum and hence much longer stopping distance and how this is amplified at higher speeds. A stupid idea to increase the speed limit with no consideration to this. Perhaps there are some long, straight roads with great visibility but the vast majority of our nations roads are not at all suitable for this. Very sad to think, but I guess we have to wait for the invariable accidents where the family in their broken down car around a bend in the road, or the innocent farmer on this tractor are ploughed into from behind by 40 tonnes of metal going 50% faster and 50% less able to stop in time than they were before…

  8. Ian says:

    Increasing the speed limit may also encourage haulliers to use rural roads more often instead of congested motorways. So we may also have more lorries on these roads, as well as faster lorries. I wonder whether they also factored in to their (doubtless rigged) cost-benefit analysis the greater damage these extra and faster vehicles will do to the carriageways of such roads when they brake?

  9. Nat says:

    Its worth bearing in mind that the change in speed limit brings HGV speed limits into line with those in the Netherlands, where HGVs (and cars) are limited to 80 km/h (~50mph) on all-purpose roads – this is for similar reasons to those stated by the DfT – to reduce speed differential between vehicles, and to reduce the incidence of overtaking (even to the point is facilitating outright prohibitions on overtaking). See page 19 of the Dutch equivilant of the Highway Code, at A default 50mph speed limit for HGVs in rural areas is not in itself Sustainable Safety, but it is completely consistent with it.

    You’ll note that in the Netherlands differential speed limits only exist for situations where faster vehicles can overtake the slower safely – trucks only have lower speed limits for cars, for example, on autowegen and autosnelwegen (motorways), which either are designed or are required to be upgraded to provide safe opportunities to overtake, and to prevent vehicles crossing into the path of oncoming traffic.

    Of course, lower 60 km/h limits are widespread in rural areas off main traffic routes; these apply equally to HGVs and other motor vehicles.

    I don’t suppose that safety is the DfT’s real motivation; neither does the change help cyclists. But it seems to me counter-productive to campaign for the advantages of Sustainable Safety for cyclists while complaining about steps towards sustainable safety that benefit others.

    The real problem in the UK for cyclists in rural areas is the failure to provide adequate cycle paths alongside traffic routes, and away from traffic routes, the failure to restrain the volume, and secondarily, the speed of motor vehicles. The default HGV speed limit is largely irrelevant to this. The hand-wringing around this is a distraction from the real problem, and the solution(s) (and dare I say, one the DfT welcomes, as it make us look unreasonable, and moves the focus away from lack of investment and competence in the design of cycling infrastructure).

    If anything, it would seem to be to be more constructive to welcome this baby-step towards sustainable safety, and up the pressure to go the rest of the way – lots of stuff not particularly relevant to cycling (reduction in the speed limit for cars to 50mph, altering road marking patterns to encourage this reduced speed, allowing for the designation of ‘autowegen’ (essentially non-motorways restricted for the use of motor vehicles only, provision of obstacle-free verges, introduction of 40mph zones away from main routes, provision of parallel roads for agricultural traffic, etc etc etc), but importantly for cycling, the provision of cycle tracks (or parallel roads where this is satisfactory and helps remove speed differential issues around tractors) along all main roads, and the restraint of traffic volumes away from these (as well as the construction of cycle tracks along busier minor roads or those carrying cycle routes).

    • Yep, that’s absolutely the right way to proceed. I was just annoyed about the use of the logic of reducing speed differentials (which is absolutely correct), while completely ignoring the speed differentials that are actually being increased between these vehicles and vulnerable road users.

      I’m certainly not arguing that HGVs should be kept at 40mph on the grounds of sustainable safety – I don’t suppose there’s much difference between HGV-bicycle interactions at 50mph than there is at 40mph! It was more that the invoking of safety as a justification rings very hollow.

      To put it another way, I don’t really care if HGVs are travelling at 50mph on single-carriageway roads if those roads are designed appropriately, and cycling is catered for separately.

  10. rdrf says:

    ” It was more that the invoking of safety as a justification rings very hollow”.

    But when people say “road safety” they are always concerned about increasing the power and freedom of the group(s) they represent.


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