Vehicle width restrictor on road doesn't work as planned because people are bad judges of their vehicle's width

Originally published at: Vehicle width restrictor on road doesn't work as planned because people are bad judges of their vehicle's width | Boing Boing


There’s some seriously high speed crashes in there. Even though the people in those are at fault it still seems unsafe to have that restrictor system in the road.

How does it work, anyway? Unfortunately the actual poles are obscured behind the wall. What do they look like that they catapult the cars that high?


It doesn’t even look like all of those cars are actually that wide. Is the thing causing accidents for vehicles that are just too far to one side?


This might shape up to be the UK’s version of the 11’8" bridge. @wazroth, fire up your bingo-card builder!

That’s my impression. This happening as frequently as it does, even allowing for some speeding drivers, indicates a possible design flaw.


This video has shots of the set up.

A big part of the problem seems to be that there is a curb cut on the left, allowing the left wheels to ride up the curb and hit the first bollard on the left (and in the UK, the left is the passenger side, so it’s harder to judge the distance perfectly). The curb on the right, on the other hand, is an island with a curved curb that will tend to guide the right wheels around it.

Note that there is a restricter on the opposite side of the street, too, but without a curb cut just before the bollards. I don’t know if it is as narrow, but it apparently doesn’t cause any crashes. Which makes it seem that having a curb cut right before the bollard is the issue.

Here is a different angle of the set up all the cars are running into, showing the curb cut before the bollard:


Would a textured road surface ahead of it prevent most of the accidents, do you think? Just something to let people know that they need to pay attention. Maybe build the thing up into an actual tunnel? It kind of makes sense that the area that is too narrow for some vehicles might be cobblestoned anyway.


Seems a pretty severe punishment for having a fat car.

Couldn’t they just have static poles that also don’t let wide cars through rather than these smashy smashy things?


Driving vehicles with lane centering technology seems to teach everyone that they are a poor judge of whether they are in the center of the lane. If only the bollack builders would learn this.

If this caught a pickup truck in the USA, we might finally get the South to secede.


This came up on Jalopnik yesterday. The commenters are completely unsympathetic, but the reality is that if this is happening this often, something needs to be fixed. This type of crash is known as a “small overlap” crash and is particularly deadly for causing rollovers (the Jeep Wrangler just failed this test spectacularly).


Yeah, this is happening in a country where there is no shortage of narrow lanes, too. Most Jalop readers are used to driving in the US where lanes are ludicrously wide unless you are in an urban center that built up prior to 1920 (and even then there might be 1 way streets to avoid narrow lanes), so they can shut it.


A local fast food restaurant has some safety bollards set up near their drive through window. They are just a rainbow of different paint colours at this point from all the cars rubbing against them.


Most people look down the centre of a lane and assume the car is central. It’s in the uk so cars will be offset to the left. It’s good to see that the police are no better than most. 2.1m will fit some pretty big (European) vehicles.


Am I supposed to feel ashamed that I don’t know the exact width of my vehicle? They seem to think so.


I used to know… on my 4x4 that I took off-road! I am pretty sure that my tires still kissed the curb on occasion.

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Put a hyphen in “vehicle width” in your headline; it’s a compound adjective.


“Widen the road!”

“Narrow the vehicles!”

There is so much wrong with this. With an overhead obstruction, whether a vehicle can pass is an absolute: you just need to compare the height of the vehicle and the height of the obstruction and the problem more or less takes care of itself, so to speak.

Not so here: not only does the vehicle need to clear the bollards (and whomst among us really knows the exact width of teir vehicle?), but the driver has to make a judgment about the vehicle’s position relative to the bollards. Notice that most of the wrecks are such that the passenger side clearly hits the left bollard – because this is the position where it’s hardest for the driver to judge position. Most of the wrecked cars are narrow enough to make it, but hit anyway. Partly, I imagine, because drivers are used to leaving a “standard” clearance on the (more visible) driver’s side and trusting intuition and typical road geometry on the less-visible passenger’s side.


“Never mind the bollards”


You should be if you drive your car into things.


What the drivers have to do is slow down. They are all moving too fast for a narrow gap.


The driver certainly bears some blame, but there are even a few vehicles in the video that creep right into the bollards. This setup has zero respect for the basic facts of human factors engineering.