At great expense, and considerable disruption, on an already busy section, the new concrete barriers on the central reservation to the M60 to the SE of Manchester are now complete.
On a recent trip to Plymouth, I noticed several new installations of this type at various locations.
Does anyone know the reasoning behind this new idea?
Running through my head is the possibility that time and expense of Armco repairs will be eased, but I would have thought that considerably larger costs will result in vehicle damage, and I worry about increased passenger injury and death.
I thought that the advantages of Armco were its low cost, and softer collision response.
Anyone know Anything?
Neil
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I read somewhere (Auto Express?) a while back that they were trialled on the M25 and that they are designed to prevent cars from going through conventional crash barriers and into oncoming traffic as seems to have happened quite a bit recently. I also recall that since being installed on the sections of the M25 that there had been no instances of vehicles crossing on to the other carriageway. I may stand corrected though..
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The key is in the shape of the concrete barriers (if its the type I think)
It has a wide base, with a curving "bottle" shaped cross section. They actually gather up the tyres of the car,and point you the right way, albeit with much scraping of the bodywork. Its also harder for a car to "jump" the barrier (as lorries and big 4x4's do with armco)
Unless you hit the concrete section at 90 degrees its just as safe as armco.
See the armco thread about why its there. Its not to save you, but save others from you.
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TourVanMan TM < Ex RF >
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The key is in the shape of the concrete barriers (if its the type I think) It has a wide base with a curving "bottle" shaped cross section. They actually gather up the tyres of the car and point you the right way albeit with much scraping of the bodywork.
We have these along some of our local motorways, and at the time they were installed, it was explained that the above is true, and that a big problem with armco is that it is 'unpredictable' in how it crumples, especially at differeing speeds.
At least with the concrete, the driver who finds himself shunting the barrier will be steered along it, as opposed to bouncing off in a random fashion.
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Right TVM, and right Ian. There are a lot of those concrete barriers around. The 'much scraping of bodywork' is to slow the car down safely (to the occupants, that is). And I think the profile of the barrier tends to keep the front wheels turning into it.
Armco has different types of mounting, and has to be fitted correctly (overlapping so that a car travelling in the direction of the traffic can't catch the end of a length of armco and be speared by it). Cases of vehicles speared by incorrectly-mounted armco have occurred, as have crumple accidents. .
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Armco is much more complex that that lud. Its quite clever stuff. The theory is that its a "ribbon" and actually not very strong except in tension. Its designed to give, stretch, the posts to come out the ground as you pass, and gather the car up and point it the right way and if the joints dont stretch, it breaks and it all quickly goes to rat poo.
Thats why it had big concrete ski jump ends, to make sure the ends of the ribbon are firmly anchored into the ground.
Trouble with Armco is that its set at car height, if it was any higher it would saw through your roof supports and have your head off in a jiffy. Beiong so low means that big 4x4's and lorrys can sometimes "climb" the armco into the path of oncoming traffic.
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TourVanMan TM < Ex RF >
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Well, thank you for that TVM. But it doesn't always work as it's supposed to and overlapping it in the wrong direction has caused spearings.
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Indeed. I agreed with you and more. Overlapping it the wrong way snaps it as well. So not only do you get speared you end up in the wrong carriageway.
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TourVanMan TM < Ex RF >
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which fits neatly in to the Armco thread about lengths of armco starting at working height.
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Aim low, expect nothing & dont be disappointed
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A link here explaining the benefits of concrete: safermotorways.co.uk/feature31.htm
(The quicktime video took ages to load for me, couldnt be bothered to wait).
www.concretebarrier.org.uk/
Its interesting (to an engineer) when you read the construction specification, how simple and lightly reinforced it is.
They have had them in the US for years and elsewhere as Ian says.
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I think this one is anchored down a bit better than the standard motorway stuff!
www.youtube.com/watch?v=UtFBuJbzjLE
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as i said, not a good idea to hit concrete barrier at 90degrees.
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TourVanMan TM < Ex RF >
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