If you’ve driven around certain parts of Korea, Europe, or the United States, you may have seen a curious construction along the side of the road, almost as if someone had assembled a whole bunch of plastic lifebuoys into a guardrail. These are a relatively new road safety technology known as “rolling barriers.”
If you’ve driven on the highways and byways of most countries, you’re familiar with traditional steel guardrails. They come in various types and sizes and generally do an acceptable job of capturing errant vehicles that are spearing off the roadway.
Rolling barriers attempt to improve on old-school guard rails by doing things a little bit differently. They aim to reduce barrier penetration and improve safety by use of big plastic rollers. Let’s explore how they work, and look at how they perform in real-world crash tests versus more traditional steel barriers.
Roll On
Roller barriers have been developed by multiple companies around the world. Korean company ETI is one of the most well-known, but they are also manufactured by Shindo Industry and KSI. Each company’s design varies to some degree, but the basic concept is very much the same.
The large plastic barrels of the rolling barrier are installed on posts at even intervals. When hit by a vehicle, the plastic barrels not only deform to absorb the impact, but also spin about the vertical axis, turning some of the impact energy into rotational energy. In turn, rather than the vehicle continuing through the barrier in a straight line, the vehicle is instead deflected to a degree, continuing in a path more aligned with the barrier itself.
This deflection action is one of the key features of the rolling barrier. Indeed, the point of guard rails is often to prevent a vehicle passing through to whatever lies behind—whether that be a sheer wall, a footpath, or a drop off a cliff. The rolling barrier does a good job of redirecting an impacting vehicle back onto the roadway rather than simply absorbing energy as it passes through to whatever lies beyond.
It’s a controversial point in some contexts. If we’re driving along a road, we perhaps wish for an errant vehicle to leave the roadway and remain off it after a crash. However, in many cases, it’s safer for a vehicle to remain on the road after hitting a barrier rather than perhaps spearing off into a ditch or traffic traveling in the opposite direction. The video below is a great example of this behavior, showing a rare comparison between regular guard rails and a rolling barrier under the same conditions.
These rolling barriers have largely remained in obscurity, despite having been marketed by manufacturers for the better part of a decade. The have been installed in various locations around the world, but remain relatively obscure compared to more traditional guard rails. This can largely be put down to their novel nature, and the fact that their additional complexity adds cost versus traditional guard rails, which is a point against them in many contexts.
Their obscurity is not due to any issue of performance. Manufacturers all proudly display their MASH test results at the TL3 or TL4 level, approving them for use on expressways and other dangerous high-speed roads. In the latter case, this requires the rolling barrier to safely deal with a 2425-pound passenger car traveling at 62 mph, a 5004-pound pickup truck traveling at 62 mph, and a 22,046-pound rigid truck traveling at 56 mph.
Watching massive vehicles slam into these barriers at steep angles really shows their capabilities.Â
As these tests demonstrate, the barriers can handle even off-axis impacts from very heavy vehicles. The rolling barrels often tidily deflect the vehicle, which helps keep it on the roadway. As a bonus, their greater height compared to traditional designs tends to reduce vaulting, penetration, or otherwise flipping the vehicle on its roof or side.
These rolling barriers largely remain a curiosity rather than a mainstream piece of road infrastructure. Regardless, they are a unique solution to the guard rail issue and can be readily installed in many jurisdictions around the world where TL3 or TL4-grade barriers are required.
Now, if you see one of these unique barriers on the road, you’ll know exactly what you’re looking at. You can even gleefully explain their value to your passengers, who will surely appreciate your knowledge. Happy motoring!
Image credits: KSI, Shindo Safety, ETI
Top graphic image: Shindo Safety
There is a guard rail end cap near my house that gets hit every 4 to 6 weeks. Each time they replace it they have a new improved spring device on the end, I hope they put these in
Um…I know cost is part of the problem with installing these in more places…but I think it’d be pointless without cranking these numbers up a bit. I honestly wonder how many <=2,425 pound passenger cars are out there at this point, and add on how many of them drive <=62 mph on a highway.
Roll out the barrel, we’ll have a barrel of fun . . .
What’re the odds one of these barriers will deflect you, out of control, right back into the stream of traffic? Not zero, I suspect.
If you watch enough dashcam crash videos, even concrete barriers do a pretty darn good job of deflecting the out of control vehicle back into the road into other vehicles or clear to the other side where it ping-pongs off the metal guard rail.
True. I just figure these might be better at it.
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Even better, demonstrate! That’s why you got the damage waiver, right?
I’ve seen a LOT of these kinds of wheels in Tibet, but they act all uppity whenever you smash your car into them to make them spin. “Blah blah blah nirvana karma dharma” and all that. /s
On the plus side of this idea, it’s probably the safest version of FSD we’ll ever see.
I expect the expense of these (purchase price) as well as the repair costs after an intrusion, are major factors in the rareness of these in the US.
Looks a little easier to just repair-replace concrete barriers, but based on the current situation in DC I fully expect to see bundles of old newspapers stacked along the sides very soon. As always YMMV.
The other thing is that these are supposed to rotate, and with how little state DOTs maintain things thanks to sprawl and funding these will likely be no better than regular guard rails after a few years when the sun hardens the plastics and the salt rusts the bearings. Other places have actually functioning governments that can take care of things.
This looks so much less dangerous than the wire cheese slicer that would easily dissect a motorcyclist in a collision.
Ah yes, the highway garrote “guard”. It slices, it dices, and cleans up oh so easily.
Why not just be like Colorado and let people fly off guardrail-less roads and plumate down mountainsides?
Where I live the steel cable dividers that wrap the vehicle up seem to be popular. (Mostly between lanes of opposing traffic)
Yeah, like the Million Dollar Highway between Ouray and Silverton? The first time I drove that I was southbound with the drop-off immediately to my right, in a rented RV, and a blood vessel had burst in my left eye so everything was blurry. Lived to tell the tale!
I’m told it’s because guard rails don’t allow snow to be plowed over the side.
plows can easily push snow over the guardrails. or they use one of these:
https://fairmfg.com/wp-content/gallery/948d/product-948d-14-min.jpg
I thought is was money?
Yep, way easier to plow the road without guardrails, especially when clearing avalanche debris that commonly ends up on the road. The main cliff section isn’t too bad now after they widened it maybe 20 years ago. There are guardrails in some key spots, one of which had a piece of bumper from my family’s 80s volvo wagon stuck in it for years when I was growing up after a low speed ice incident.
At least you weren’t one of the people who get so scared they just stop in the middle of road, and have the authorities finish driving their RV for them.
Whoa! People do that?!? My wife was too afraid to attempt it, and insisted I drive with my bad eye, so I guess that’s about the same. As a man I have too much pride to stop and have someone else drive.
Apparently so, a couple times a year, according to a CDOT employee I talked to while waiting, after an avalanche almost hit the car in front of us last year and covered the road.
Oof. Largely bingo, anyone?
Bigly.
This seems pretty laughable. Miata aside, can you even buy a 2400 lb car new?
And while 60 mph might be reasonable for a 2 lane highway, I’d hardly call it a severe enough test for a “high speed road”.
A more realistic test would be a 4000 lb car hitting the barrier at 80 mph, an impact carrying almost 3x the kinetic energy as the example.
Yes in places other than the united states.
I was thinking same – the weights need roughly doubled.
The rigid truck has 2.7x the KE of your 4000lb/80mph car though.
Given these are primarily used in countries with access to smaller cars and also experience lower travelling speeds than the US, I would expect the ~1100kg car is there to test that nothing untoward happens if you hit it at speed but with less mass.
The tests are the same for all guardrails!
But do we really want large, out of control, now seriously damaged vehicles being shunted back into the roadway where they will hit other people and cars and causing long backups for the rest of us who aren’t driving like morons/relying on FSD?
Darwin and I are fine with letting them roll right over the cliff into the ocean.
*cue distant fireball – then splash*
You wanna make things really safe?
Put huge steel spikes alongside the road pointing at oncoming traffic. You hit it, you’re swiftly stopped and are no longer a danger to anyone else on the road.
Game Over.
Back to oxen and a cart, got it.
Great for people shoved off the road by terrible drivers
Shoved off the road by Karen in a grey RAV Bore while applying makeup and texting oblivious to all the Mayhem* she is causing.
*MAYHEM is a registered trademark of Allstate Insurance Company.
All it takes is lifting off and braking to let Karen spike herself.
I see you’ve played BeamNG before.