Bollardian nightmare?

Rising bollards in Silver Street, Cambridge

Rising bollards near Darwin College, Cambridge. A man was killed here in May 2006 when his car hit the right-hand bollard; see third photo below.

Many thanks to Steve Portigal and Josh for suggesting this subject!

Bollards which automatically retract into the road surface to allow certain vehicles to pass, and then rise again, are becoming increasingly common on public roads in the UK; whereas previously, they might have been used at the entrance to a private car park as a more visually appealing alternative to an automatic barrier, many authorities are now using them to enforce traffic control in urban areas, with the category of permitted vehicles including buses, emergency services, postal vans, and so on. (I’m not sure about taxis; I think this varies with city*). The recent compilation of CCTV clips by the Manchester Evening News (link via BoingBoing) showing ‘non-permitted’ cars and vans hitting rising bollards in Manchester, as the drivers try to follow close behind permitted vehicles has got a lot of attention, with reactions ranging from “stupid drivers deserve what they get” to “how is causing thousands of pounds’ worth of damage to punish a minor crime ever justifiable?” (There’s also this video showing a higher-speed crash – not sure if this is in Manchester too).

Rising bollards in Manchester Rising bollards in Manchester
Stills from the CCTV compilation: the rear nearside wheel of the black 4×4 is off the ground. The van’s windscreen has been damaged by the driver’s head hitting it.

As an architecture of control, what can we say about the rising bollard? Is it merely a ‘restriction of access’ device, like a padlock? Or is it actually intended (to some extent at least) to damage the vehicles of non-permitted drivers, and injure them?

The official line would be the former, of course, but going by the dominance of the “stupid drivers deserve what they get” viewpoint in public comments on the Manchester video, I would suggest that a vindictive streak is pretty significant, and there’s no reason to think it might not also be among traffic planners.

The extensive (25 page) discussion at the road enthusiasts’ site SABRE also contains both points of view, and others. One logical argument which is well made, I think, is that if the drivers expected to damage their cars, they wouldn’t have tried to follow the buses. Therefore, the warning signs/road markings (knowledge in the world) or their prior experience of these systems (knowledge in the head) cannot have been sufficiently clear to discourage them from trying to sneak through. Yes, they knew that they “weren’t supposed to” drive through, and knew that buses were, so they tried to sneak in behind, but the drivers can’t have been fully aware of how quickly the bollards rose, or they wouldn’t have attempted it, would they? Most people don’t deliberately wreck their cars.

This is an important point. The system is not designed to be forgiving of mistakes. Now, we can say “well, why should it be? Those drivers shouldn’t try to break the law,” but in the real world, people do make mistakes. That’s why pencils have erasers. A car driver following a bus may have his or her vision of the warning signs obscured, and may be driving at a perfectly sensible speed, but still hit the risen bollards. A car driver following another car which externally looks like any other, but which is (for whatever reason) a permitted vehicle (with a transponder on board) may see the warning signs, and take them in, but, seeing the bollards lowered and the car in front driving at a constant speed, may assume that the bollards are disabled or permanently down, and so continue at exactly the same speed, and not be able to brake in time to avoid hitting the risen bollards. Bollards in some cities are only operational at certain times of day, and in certain directions; unless the warning signs themselves have a very clear variable display (Cambridge’s are fairly good), can we really expect drivers to read the times from the sign as they go past following another vehicle?

There are two much more sensible systems suggested in the SABRE discussion:


If this system is needed, then surely there should be conventional red lights with the bollards only rising a few seconds after the lights have changed to red (as with a level crossing). If you’ve never come across such a thing before it is not remotely obvious.

‘True Yorkie’

Perhaps a better idea would be to have a ‘vestibule’ system, with 2 bollards, spaced exactly a bus length apart. As the bus passed over the first lowered bollard, it’d stop immediately for the next bollard. As it waits for the second bollard to lower, the first would raise. Any car that tried to get in with the bus would have to shunt the bus to fit into the vestibule.

Either of these would be much better than the existing system. Both ‘design out’ the likelihood of mistakes – the vestibule system especially so.

Rising bollards in Silver Street, Cambridge: the driver of the Shogun was killed; image from Véro
The fatal accident at the Silver Street bollards in Cambridge (photo from Véro’s blog); this photo of the same bollards as my photo at the top of this post.

To a large extent this issue seems to come down to a debate on the old “if you’re not doing anything wrong, you’ve got nothing to fear” argument. Again, it’s a subject for a future post** but I find the repeated use of this, by politicians especially, to justify every erosion of established freedoms, both sly and egregious: there’s a reason why I can’t legally shoot you if you walk up my garden path, or electrify my car body shell (OK, it’s fibreglass, in fact, but the same principle applies). Perhaps the “if you’re not doing anything wrong, you’ve got nothing to fear” brigade would let happily let the authorities read all their personal correspondence, and indeed would be happy to have all private property covered in mantraps and landmines to enforce “trespass prevention”? After all, “if you’re not doing anything wrong, you’ve got nothing to fear.”

Jeremy Wagstaff applies this kind of thinking to the bollard issue to demonstrate its absurdity, and its distasteful corollary:

My tuppenny’s worth: I think traffic maiming (as opposed to traffic calming) is a great idea but doesn’t go far enough. We need similar measures to punish, sorry deter, drivers who routinely flout the law and common decency. Why not, for example, deploy the retractable bollards elsewhere, like

* the centre of a restricted parking space, so it would rise at the end of the designated period, impaling the vehicle if the driver had overstayed his alloted time;
* at random points on the hard shoulder on toll roads/motorways so that cars illegally using it as a fast lane would be impaled, or flipped over into an adjacent field

Where necessary, bollards could be replaced by other features such as

* a mechanical arm, installed on the roadside and connected to a speed sensor, which would crush cars passing by too fast or too slow, depending on what irritated other drivers the most.
* or cars driving through built-up areas too fast would be taken out by snipers deployed in trees/tall buildings. If necessary the snipers could be automated.
* cars straddling two lanes or changing lanes without indicating first would be sliced in half by retractable blades intermittently rising out of the demarcating lines
* motorbikes using the sidewalk (a particular bane in my neck of the woods) would risk having their tyres slashed by strips of spikes activated by the annoying sound of approaching underpowered Chinese-made engines.

Norms, restriction and punishment

It’s worth thinking about the norms of restrictions and warnings we encounter in everyday life.

Many – in fact most – signs indicating the prohibition of particular behaviour do not suggest immediate punishment to us. The sign may say “Do not drop litter” but most people who do drop litter know that unless someone is watching, and decides to do something about it, they will get away with it. A road sign may say ‘No Parking”, but if no-one’s around, is it wrong to stop? Is it a crime if no-one finds out, and it doesn’t affect anyone?

We can laugh about falling trees in the forest and Schrödinger’s cat, but I think that for most of us, there is a very clear mental distinction between “incorrect” behaviour which we know will be “punished” immediately by the realities of the system (e.g. pointing a gun at our face and pulling the trigger, or driving through a level crossing barrier when a train is coming), and “incorrect” behaviour which we know is technically wrong, but which only the fear of being caught (and punished) stops us doing. Most drivers speed, but they wouldn’t speed if they knew there was a police car behind them.

So, our mental model of a ‘No Entry’ sign is that it signifies an arbitrary restriction, but one which carries no immediate punishment, unless, say, it’s a single-track road and something’s coming towards us at speed. If we ignore the sign, we might find we’re going the wrong way down a one-way street, or we might get caught (by camera or by police on the ground), but that’s a risk that people may take if they perceive it to be very low. If we can see that it’s not a one-way street, and we can see other vehicles passing that way, then there is apparently a fairly low risk to ignoring it. Our expectation is that we will get away with it.

When bollards then rise out of the road immediately in front of us, our mental model is proved wrong. The norm is shattered. This is a system that immediately punishes those who infringe the No Entry sign. This is a familiar, apparently docile ‘Keep off the grass’ sign accompanied by snipers watching very carefully.

Now, the UK’s Department for Transport clearly recognises something along these lines: the norms of the bollard systems are different to those drivers may have come to expect, and an additional aspect is also identified: that of the “control of all vehicles/control of individual vehicles” distinction:

Established practices of traffic control using traffic signals do not control separate vehicles; streams of vehicles are controlled with drivers able to see the signals from a significant distance. Rising bollards are normally used to control individual vehicles in that they are raised each time a vehicle has passed over them. The requirement, therefore, is for short range signalling… Unless drivers have a clear view of the bollards, an indication should be given to drivers that the bollards have fully retracted.

In conjunction with the vestibule system suggested in the SABRE quote above, that seems the most sensible approach to take. The DfT also has some other sensible guidelines:

Three wheeled vehicles, motorcycles and vehicles with trailers, for example, may not be sensed by the vehicle detectors used with automatic bollard systems. It will almost certainly be necessary to provide alternative means of access for some classes of road users or vehicles. The possibility of a device rising under a wheelchair or pushchair should be taken into account. The risks could be mitigated to some extent by providing suitable alternative access adjacent to the bollards, and by using a coarse road surface to divert pedestrians away from the bollard installation [interesting! – see also the pebble paving to make barefoot walking uncomfortable, mentioned here]. Whilst most applications will be to enable the passage of one vehicle at a time, there will be instances where two or more vehicles attempt to pass through in close succession. The system should ensure that bollards cannot rise beneath a vehicle because of the danger this would create. It is better to risk a certain amount of violation by “tailgating” vehicles, rather that put road users at risk. Any system, however well designed, will fail to operate correctly on occasions. The system should fail to a safe state, ideally with the bollards retracted. In the event if an accident the emergency services may need to override the control system and retract the bollards.

Still, for all the effort (and costs) involved in installing and running the bollard systems, would it really not be better to look at the subject from a greater distance? The roads drivers want to use are in many cases roads which used to be open to all traffic – indeed, in Cambridge, Silver Street used to be one of the main routes into the city centre, part of the old A603 from Bedford. The current alternative route from west to east is significantly longer and almost always very congested. It passed close outside my window when I was a student; I know. It’s understandable in many cases why drivers want to use the old route.

The real issue that needs to be addressed is why people want to drive into these areas. There is always a reason; people are rarely “stupid” with no explanation.

*I’d like to get into the “are taxis public transport?” debate another time: not now though.
**There was a quite astonishing article I read about a year ago where a police chief in a small US town had (seriously?) suggested putting CCTV inside every home in the community, for constant monitoring, and used the same “if you’re not doing anything wrong, you’ve got nothing to fear” argument; if I can find this again, I’ll post the link.


  1. There’s also the inequity of experience.

    Perfectly competent road-users may not have equal opportunity to learn otherwise obscure behaviour of such systems.

    1) It’s taken me a while before I’ve learnt that some barriers have no intercom or access requirements, but are merely present to require a vehicle to stop before proceeding upon automatic raising of the barrier.

    2) Locals can often whizz through traffic calming, width restricting poles, leaving newcomers to slam on the anchors as they recognise the peril only just in time.

    3) Some traffic calming measures – especially width restricting poles – actually encourage daredevil behaviour for excitement and michievously luring lesser drivers into their unpleasant encounter.

    Square road bumps that fit between the wheels are similar – they permit locals to exploit rabbit runs at full speed whilst slowing cautious visitors.

    4) The rising poles, and their behaviour also favour locals while punishing cavalier strangers.

    5) Speed cameras also train regulars, whose unexpected brake-lights confuse visitors.

  2. I don’t see why the bollards have to be so rigid. Certainly there should be a break-off point of force that is well below what is required to total the car.

    If it were me I’d use the same system & timing but utilize a CCTV camera (or a still that akes a photo on impact) and a breakaway bollard that is rigid enough to damage the bumper and coated with a high-marking paint (if such a treat exists – basically something that will easily transfer to any vehicle that comes into contact with it).

    The prospect of the bollard would likely ward off the vast majority of people, but for the true idiot drivers they’d get a dent in their bumper, some distinct paint marks and a photo to help law enforcement deliver the pricey ticket in person at a later date.

  3. Dan

    Thanks Crosbie and Ryan – those are some very good points.

    @Crosbie: The barriers intended merely to make a driver stop before proceeding (with no authentication needed) are an especially interesting method of control – I’d never thought of them in that way before.

    Your point about ‘encouraging daredevil behaviour’ certainly rings true to me. I perhaps shouldn’t admit it, but having a very narrow car when I was younger (a Reliant Kitten) did used to encourage me to explore what I could get away with. Here, for example, somewhere just north of London Bridge, we drove down a narrow ‘cycles only’ alleyway blocked by a central (manually folding) bollard: the car was narrow enough to fit past the bollard:

    I shouldn’t be proud of it, but in a way I am. It was night, there was no other traffic around, and at that time I don’t think there were any cameras.

    @Ryan: That’s a very sensible suggestion. It wouldn’t severely injure anyone, or cause massive damage to the car (or to the bollards, assuming they were designed to collapse in a controlled way), but the CCTV (and paint or dye spray) would allow the identification of the driver, and be a sufficient deterrent to others.

    The fact that there is CCTV covering the bollard installations anyway (hence the video clips) suggests that if there were sufficient motivation, every transgressor could be identified anyway, without any bollards or any damage to anyone or anyone’s vehicles. There used to be a ‘short cut’ road near where I grew up which was nominally ‘buses only’, with cameras at both ends, although it soon became known among some locals that no-one ever watched the cameras so it was ‘safe’ to use.

  4. Humans are designed to explore the parameters of their environment and to adapt to them.

    I once became familiar with a particular set of width restricting poles (a long time ago 😉 ) and used to accelerate from a sedate 20mph to a vigorous 40mph in order to best appreciate my ‘skill’. The poles delimited a road that spanned a boundary between a residential area and a non-residential area. The road itself, whilst a typical narrowish lane, was otherwise free of peril.

    I knew the road before the poles, and had always tended to take the lane sedately. The poles actually inspired me to increase my speed.

    Another example is the automatic ticket barriers at railway stations – for pedestrian passengers. Even though I am in possession of a valid ticket I am sometimes inspired to tailgate (wait for someone else to approach the barriers, then switch ‘lanes’ to walk closely behind, closing at just the right time to be mere millimetres away from the person in front’s posterior, through the barrier with them and then immediately decellerate to pretend everything is normal – in case they later turn around having been tipped off by any inadvertent clothing/baggage contact).

    I’ve also quickly straddled 4 foot high palisades to avoid 200yard walks to negotiate ticket barriers. Now they have got wise to this and are erecting signs that ‘require’ passengers to use ticket barriers even if they are in possession of a valid ticket.

    At least there are still no signs that require passengers to insert their ticket into the machine and/or to enter one person at a time.

  5. It seems the Brits are increasingly fond of this sort of creeping street-level fascism. Here in Canada I’ve not seen any unreasonable access barriers, anti-sit devices, or anything else. It seems like outright antisocial behavior (e.g. trucks using a residential road as a through road, or excessive loitering) gets dealt with by the old-fashioned method of “if someone complains, have the police investigate”. The worst I have seen being benches with center armrests, and those have uses other than anti-sleep, such as to create a barrier or separation between people sitting, which preserves “personal space” around occupants. Or actual arm-resting.

    Limiting vehicles entering a residential area has its own problems. Big trucks might reasonably be prohibited, but obviously blocking access by buses, moving vans, delivery vans, and personal SUVs is not desirable to anyone but (maybe) Greenpeace. (My own street here intermittently gets delivery vans. It has no bus route but does get the odd specially-chartered bus, mainly for a couple of mobility-disabled people living in the area. It also has no through connection to anywhere else, mind you. I myself have had takeout food delivered and, on rare occasions, more substantial and expensive goods. My having to go to the nearest post office to pick these up would have meant someone was missing the point of those services, particularly in the case of the takeout food.)

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  7. Moz

    You keep saying “accident” when you mean “crash”. Unless you’re claiming that the drivers involved did not actually mean to drive through the area in question.

    The videos I’ve seen all suggest that the motorists were deliberately breaking the law, and the faster smash the bollard is up for at least a second before the motorist hits it, so any suggestion that it was “hidden” is IMO out. Sure, the motorist was so focussed on breaking the law that they weren’t paying attention to the road, but that’s a problem in itself.

    Perhaps my sympathy is limited because I ride a bike, and so am more likely to be killed not because *I* break the law, but because some moron in a motorcar does. The idea that the moron might suffer instead does not bother me anywhere near as much as the prospect of being killed.

    It also seems like a correction to the current approach to motorists, where the fines and jail terms are grossly out of step with other, similar crimes. Kill someone with a knife because you were negligant, go to gaol. Do it with a car… lose your license for a year or two. Getting drunk and assaulting someone is much more serious than driving drunk. Kill someone in the assault and you’ve probably committed manslaughter. In a car? You might go to gaol, but you might not. Probably not.

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  11. I’ve got an idea of how to keep unauthorised vehicles away from the bollards; I’m going to sound like a twat with this one, but–couldn’t you just read the traffic signs?

  12. David

    I followed a bus too closly, did not see any signs,genuine mistake, first time in Cambridge, ballard lunched me in the air, car needs to be written off, what the f.. is that? I live in london and never missed a buss lane, this road was not even painted red like all of these tipes of roads in London. On top of that they want to me to pay for that. It’s a joke.

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