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I am curious if there is a technology that allows bicycles to run over it, but will destroy car tires. From my understanding, usually poles like this are placed on trails to prevent vehicles from passing through.

Apparently, in Russia, there is a common issue with car drivers using the sidewalk. To allow the passage of bicycles and not cars, without making the pedestrians navigate between poles, maybe some kind of technology can solve the problem while keeping everyone safe.

enter image description here

Explaination from comments: The russians have a real problem with drivers on the footpath / bike path / sidewalk. So there have been groups of vigilantes stopping a car on the footpath and haranguing the driver for bad behaviour. One thing they do is slap a huge hard-to-remove sticker on the car's window right in front of the driver. Literal sticker text translation would be "I spit on everyone and drive how I want"

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    A few strategically positioned poles can do a lot to discourage cars. It seems like anything that could destroy car tires would give pedestrians more trouble than poles would.
    – BSO rider
    Dec 8 '15 at 22:45
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    I don't want any kind of spike on my bicycle path. I would rather take may chances avoiding a pole (or German).
    – paparazzo
    Dec 8 '15 at 22:45
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    What is the second pic supposed to mean?
    – BSO rider
    Dec 8 '15 at 22:46
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    @BSOrider: literal sticker text traslation would be "I spit on everyone and drive how I want".
    – Klaster_1
    Dec 9 '15 at 6:43
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    @TimothySwan I deleted it because it had no upvotes but had argumentative comments from several people.
    – Móż
    Dec 10 '15 at 20:23
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Keeping cars off a bike path is easily done with bollards. Blocking motorbikes is the hard part and not one I've seen a good solution to, as off-road motorbikes aren't much bigger than bikes (narrower than trikes) and can be lifted over a step-over gate.

Good solid posts 1-1.5m apart will completely block cars, and the middle one can be a removable, lockable version to allow service vehicle access. Alternatively a gate can be provided next to the bike gap. This also permits horse riders. Where the primary concern is horse riders but bikes are permitted, a gate that a horse can step over is sometimes fitted. A cyclist has to dismount and lift the bike over - one thing on a lightly loaded MTB, another touring with a trailer. Here a picture of one (CC-by-SA David Hawgood via Geograph.org.uk): Step-over gate In this case it would also be possible to get a bike round the gate.

There are some truly awful attempts to allow bikes while preventing motorbikes. This Street View shot shows a gate open, but when I passed that way on a recent tour (in peak commuting hours) it was locked. You're supposed to push your bike through the slot and walk round. Mine was far from fitting - the aerobars and phone mount were too high, and the drop bars were too low and wide. I didn't have panniers but they wouldn't have gone through either. I ended up lifting the 40kg laden bike over the gate. Even that isn't an option on some of these facilities. In one case (no photo online and I'm not going back that way) the gate was over 2m tall, and required me to loosen the screws holding my aerobars, or backtrack and ride a very busy fast road.

Some care is needed in designing the layout of bollards and similar to ensure that recumbents and especially trikes can pass, but a straight stretch of path makes this easier.

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    As you say, these are primarily barriers to people with luggage, load-bikes, trailers, prams, wheelchairs or any kind of mobility issues. But they don't even slow down motorbikes much, let alone stop them. So they are worse than useless.
    – Móż
    Dec 10 '15 at 20:26
  • @Mσᶎ, the gates certainly seem worse than useless. Bollards slightly less so. But none of the spike systems can differentiate between bikes and motorbikes either, which is why I highlighted that as the problem.
    – Chris H
    Dec 10 '15 at 22:23
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There will be legal issues that make this more complicated as it seems. For example, if there is a risk that the car tires get destroyed while the car is travelling at speed, this could lead to nasty accidents where people get seriously injured or killed, including innocent bystanders. And even if only the car tires get damaged, in many jurisdictions you don't get a right to damage somebody's car just because they broke a traffic rule.

Also of course it has to be absolutely failsafe that the device isn't triggered by anything else, like people or horses stepping on it.

So the use of such devices will probably be restricted to a narrow range of situations, e.g. law enforcement, used by trained professionals with clear procedures that minimise the risk to the offender and any bystanders and a risk assessment that justifies its use in the individual case (e.g. against terrorist attacks, or in a car chase where the driver has already endangered bystanders and must be stopped at all costs).

I don't think that the wish to stop a driver using a bike path is enough justification for endangering the driver or even just damaging their property.

All the measures (that I can think of) that stop cars from entering a path are passive and obvious, so that potential offenders can see and avoid them, like bollards or gates. Even automatic raising bollards need lights and warnings etc., they can't just pop out of the ground unexpected (not that it helps much, there are loads of funny videos on youtube of drivers following behind buses through bus gates and hitting the bollards...)

So you can stop cars by restricting the width (bollards, gates), but there's almost nothing you can do against motorbikes if there should also be access for (larger) bicycles, wheelchairs, buggies etc.

From a purely technical point of view, it would probably be possible to build a barrier that uses the weight of the vehicle, so motorbikes will be stopped but bicycles can go through.

An obvious solution is a deep trench across the path that is covered by a plate held up by strong springs. If anything above 200 kg drives onto the plate, it will tilt down so the vehicle ends up in the trench, while everything lighter can pass. Or it tilts down a bit and exposes spikes that damage the tires.

However, while this would technically be possible, you'd probably get into real trouble for all the reasons above. And it gets more complicated if there's a risk that a horse or cattle steps on it, or a hiking group of several people.

With modern technology it should be possible to have a smart camera that recognises the type of object that is trying to get through and can open or close a gate accordingly. If it recognises a car or motorbike, it simply locks the gate, but opens it for any other user. I assume this will be legal, but expensive and will need much maintenance.

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  • I really liked your idea after "barrier that uses the weight of the vehicle", as I've seen videos of the opposite: a gate that opens automatically when a car or motorcycle "steps on" an actuator plate. I'm sure It can be done in the opposite way, as you describe.
    – Jahaziel
    2 days ago
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Yes, this is possible, and actually quite simple. Pedestrians would hate it, though:

  • You need a line of spikes, perpendicular to the driving direction.

  • The spacing of the spikes needs to be such that even the widest bike tires will only depress a single spike at most. The much wider car tires would need to depress at least two neighboring spikes.

  • The spikes come in pairs which are supported by a balancing beam below the road surface. If one spike is depressed, the other spike rises further out of the ground.

Since car tires would roll over two connected spikes, they cannot depress both simultaneously. Bikes, however, would only depress a single one that would give way without much resistance.

Pedestrians would hate such spike barriers, because they would frequently hit the spikes with their toes when they walk over it.

However, such destructive barriers are going to be understood as an act of warfare by motorists. And that's definitely not what cyclists want. We need car drivers to respect us, not to be our enemies. Because, let's face it, motorists have pretty deadly weapons at their disposal...

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    As a cyclist I would not trust riding over those spikes. I would doubt the balancing system and bike tyres, and wheels, can be seriously damaged by spikes that do not damage car tyres. And riding a trike, velomobile in my case, I would have even more problems avoiding the spikes than people on bicycles.
    – Willeke
    Oct 20 at 17:09
  • Bollards or poles, or other ways to stop cars, will be much better than spikes in the ground.
    – Willeke
    Oct 20 at 17:14
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    @Willeke I never said it was a good idea. I just said, that it's possible ;-) Oct 20 at 17:57
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Assuming you want to deploy them on the private road or anything the like, these even work against tanks, are not much more dangerous than just boulders and also look nice enough. You cannot easily remove them, and cannot pass through without damaging the car. There are many such structures in Switzerland, remaining from the war times. Just leave a half meter gap somewhere for the cyclist.

enter image description here

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  • A half meter gap is not enough for all cyclists: Typical handle bar and basket widths are around half a meter, some handlebars go as wide as 70cm. And that is before considering safety distances. In order for not being a nuisance for cyclists, the gap should be around 1.5m. All cars are wider than that, and you cannot stop a motorcycle from fitting through any gap that a cyclist can traverse. Oct 20 at 14:29
  • I remember having a gap of around 70 cm on my commute once, and I positively hated it. There was just way too little room between pedal and stone on both sides, and I always feared hitting one of the stones with a pedal someday. Oct 20 at 14:33

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