A couple of weeks ago, I was about a hundred yards behind a 4 wheel truck on the M56. The truck was in the nearside lane.
It suddenly moved into the middle lane, then the outside lane, then onto the grassed part of the central reservation , and then into the barrier.
The barrier did its job of stopping it while keeping it upright and within the central reservation.
And yes, I did stop at the next emergency phone to report it.
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they are slowly getting changed for solid concrete
come back from hull on the m62 and see them
or go to europe as ther go for miles over there,i poften wonder if the world wont implode due to all the concrete they must have used
im happier seeing concrete by the way,ive just seen look north and that crash caused the artic to go straight through the armco
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Yes, I thought the Armco barriers supported on posts was outlawed by Europe and due to be replaced in due course by the continuous concrete barriers.
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they also seem to plant forests between the barriers as well... suppose a full grown tree would stop most vehicles...
They definitely need something... but how often does a vehicle actually go through the barrier... would it be worth the expense of changing them from what we have at the moment... and if you had concrete ones what are the chances of achieving take-off, acting as a launch pad, as concrete wouldn't give way like armco, so would either bounce the vehicle back at high speed or launch it over into the other side... whereas armco reduces the speed and isn't as violent in the impact...
If you watch motor racing racing its well known that suspended steel plates/armco as a fence is a lot more forgiving and creates less damage when hit than a concrete wall...
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but only concrete stops a waggon b308 this is why it is better i believe,remember you are not hitting it face on so it should bounce you back to point the way you came and cut down other peoples deaths on the other carriageway
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Its not that simple, BB, it depends on how it hits the barrier, if it hits it at the wrong angle it can go through, granted, but a concrete barrier, as I said before, can launch a vehicle... and also, unlike armco, doesn't slow it down. Also much of the northern eurpoean motorway is two lane, meaning that the lorry is less likely to hit it at a sharp angle than over here, where there is an extra lane as well as a larger central reservation from what I've seen.
Too many variants for my liking to say that concrete is better than armco/wire fence, though I'll stick with my gut feeling that prefers the steel fence...
There is an alternative... cut down the ever increasing weights of lorries?!
Edited by b308 on 19/05/2009 at 20:24
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There is an alternative... cut down the ever increasing weights of lorries?!
>yes i could agree with that
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Having driven on Americas equivalent of our M Ways, they have a strange , concrete shaped barrier in the middle that appears designed to prevent large wagons and even cars from going over the top. Many of them carry big black rubber scars that I presume are from HGV tyres judging by their height. There are also large amounts of coloured scrapes at around car bumper height.
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Its all well and good stopping it going over... but what happens when it bounces back off the concrete on a narrow motorway... doesn't bear thinking about...
Just a thought but I suspect that this is one of those times when the spectacular results of a head-on collission getting into the media actually over-ride any scientific look at which would be best...
MrX (or anyone else for that matter) do you know what the stats for these sorts of accidents are? Are we making a mountain out of a mole-hill perhaps? Surely there must have been some research on this?
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but what happens when it bounces back off the concrete
At least it is going, in the most general terms, in the same direction as the cars it is being bounced back among b308. Bears a lot more thinking about than an HGV crossover on a wet Friday evening M6, surely?
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oops
Edited by Hamsafar on 19/05/2009 at 20:38
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The whole design process of barrier selection was changed recently. The change was bought about after the Selby rail disaster. The new system uses an in-depth risk based design process. Its basically an Excel based spreadsheet.
In the old days it was as easy as saying: How wide is the road, whats the road speed, whats the obstacle - hey presto you would order a certain barrier. Not so simple these days as there are a lot more variables to consider - this is why you are seeing new types of barrier.
Also, they can now use any type of barrier, as long as it has been tested to a new British Standard. There is a barrier out there which conforms to the standard (for low speed roads) and is actually made of wood.
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>>Not so simple these days as there are a lot more variables to consider - this is why you are seeing new types of barrier.
>>
Not a motorway but a central reservation barrier upgrade on the 40mph limit A309 railway bridge @ Hinchley Wood Esher has just been completed ( a few days ago).
It appears that the bridge has been strengthened and all new barriers have been installed.
I am not sure if it is a new type of armco barrier but it is double height over the bridge.
There is also a wide central reservation.
Not aware of any accidents on the bridge but there are just brick walls between the "slow lane" and the railway line.
At first glance the central barrier looks like overkill and if this barrier is deemed fit for purpose why no armco to protect the railway ?
Overall it is very hard to believe a cross over incident is a high risk at this site but it may be a relatively cheap installation as the bridge was being sorted.
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I noticed the bridge at the bottom of the A3(M) as you come into Portsmouth was reduced from 3 to 2 lanes and 70mph to 50mph a few years ago i thought just for the road works, low and behold when they went there was a big concrete and steel barrier installed on the left where the bridge goes over the A27 and the speed limit and less lanes was still in force i thought it strange for a while then thought about how much protection the old barrier would of had with a truck hitting it at 56mph, guess the 6mph speed limit reduction either makes a big difference or it's just to stop cars having fun changing lanes at a big difference in speed to the trucks. Glad they did it before a major accident.
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do you know what the stats for these sorts of accidents are? Are we making a mountain out of a mole-hill perhaps? Surely there must have been some research on this?
From www.brake.org.uk/index.php?p=585
In the UK, crossover incidents account for over 200 motorway crashes and 40 deaths a year.
At present, the majority of central reservations on major roads in England are installed with flexible steel safety barriers. This type of barrier was chosen for its containment of vehicles and minimum effect on vehicle occupants. [17] However, the Highways Agency has since changed its policy and now recommends the use of concrete barriers on motorway central reserves.
(although the above web page seems to mention some concrete makers association a bit too often for my liking)
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I remember seeing that crossover accident in Italy on youtube (HJ correctly shut the thread at the time, probably 12 months ago as many fatalities were the result).
Basically the truck involved literally turned left and crossed the centre armco at approx 70' angle...watching the footage carefully the truck went through as if the barrier was made of cheese, it didn't slow or deflect the trucks progress one bit.
We have to decide what's really needed, my opinion is at all costs trucks must be prevented from crossing, and as said only concrete will do that.
The alternative means trucks will go through, and that always results in people dying.
The steel armco may be kinder to a glancing car, but the car even if deflected or bouncing off will still be on side and going in the same general direction meaning other drivers have a sporting chance of evasive action.
A truck crossing over gives no one in its path any hope of survival, i think sometimes drivers forget just how much damage a truck can do.
Incidentally, i recommend that youtube clip to everybody, i believe it should be seen by all drivers.
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just watched it
dreadful :-(
was it suicide or a blowout?
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Perhaps we need a 'belt and braces' system, with a concrete barrier with a steel armco barrier by the carriageway. Smaller vehicles would be deflected and, hopefully, lorries would be slowed slightly before hitting the concrete.
It is a pity that the central reservations tend to be so narrow. I have often wondered if you had a plant screen inbetween the barriers, whether that would make it safer in an accident and also preventing glare one gets from drivers with badly adjusted lights on the opposite carriageway. I would nominate leylandii for the job - it has to have one good job - as it has been shown to be very good at recycling carbon monoxide into oxygen.
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Some American roads I encountered had a very wide gap in the centre which was in the shape of a 'V" but with not so steep sides. Thus a vehicle would go down the slope and travel along the middle.
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I don't think it's that rare it happened on the M3 a few weeks ago heading north near eastleigh i think.
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Having driven on Americas equivalent of our M Ways they have a strange concrete >>shaped barrier
Coming to a motorway near you and soon.
Vast stretches of the M18 and the M62 already have these concrete central reservation type barriers.
Todays fatality on the M62 just would nat happened if they had of been in place.
The 'cheese wire' barriers are the ones I do not like as a motorcyclists point of view, I certainly would not like to meet with this type unless I was sat in my comfortable cage.
Edited by Tron on 20/05/2009 at 00:28
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Higher Armco, please, not concrete.
Ever watched NASCAR pile-ups?
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Oddly no-one ever mentions speed here.
Kinetic Energy is 1/2 M V squared.
Reducing weight (effectively mass) as mentioned has less effect than reducing speed.
So surely the quickest and easiest thing to do is to reduce the motorway speed limit for cars and lorries. And doesn't this kill the arguement about speed not being a cause of crashes - a slower lorry won't have the energy to go through the barrier!
Waits for explosion . . . .
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The main reason for the greater use of concrete barriers in the central reserve is to reduce maintenance. Both in-service maintenance and after an accident. It reduces the amount of time that people have to work in the carriageway.
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Local news were reporting that the repairs on the M62 finished about 6am this morning. The vehicles were off scene by about 8pm.
Even with concrete surely the damage has to be assessed and the concrete strength tested to ensure it doesn't need a section replacing?
Vegetation sounds good, but it needs managing and closing motorways to allow trees to be cut won't go down well with anybody. It's bad enough when they have to trim the weeds.
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The trouble with vegetation is two-fold:-
1. Vehicles can get 'lost' within the vegetation and may not be seen by other vehicles, especially in the dark.
2. Vehicles can get jammed into the vegetation and the occupants may not be able to open their doors.
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3. A tree is the last thing you'll want to hit if you want to survive
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On past threads many BRs moan about the lengthy motorway closures following crashes. Some are due to fatalities and many are due to barrier repairs. The only answer is to install the concrete design.
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Huge wide central reservations are all very well in the US. In the UK we have a shortage of land, thus they are not appropriate.
I too very much favour the shrub vegetation favoured by the continentals. It prevents on-coming headlights from dazzling, and is soft but impenetrable. Briar Rose for choice.
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Link to Highway agency explaining policy on barriers
www.highways.gov.uk/knowledge/11569.aspx
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As well as prevention of crossovers, I would also like to see central reservation barriers which prevent rubberneckers from practising their ghoulish, anti social activity. ]
I have lost count of the number of times I have been delayed in miles of slow moving traffic for half an hour or more not because of a problem on my side of the road, but because someone has crashed on the opposite carriageway and people are stopping to have a gawp! If they couldn't see, it wouldn't happen.
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Its not just lorries that can go through - I was behind a fatal accident on the M23 where a Merc van must have had a blow out, and veered right into the barrier and flipped over it into the oncoming peak time traffic - not funny to witness. At the time the barrier was not the armco type but one of the pre-tensioned wire ones.
Having just returned from a long run in France on the Autoroutes by compariison to the UK barriers, the concrete barriers do seem to be fairly substantial and not sure a comparable accident could happen both because of the shape and height of them, and I assume the foilage also on top helps to stop any flying debris spilling over as well.
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Oddly no-one ever mentions speed here.
---Waits for explosion . . . .
That would be putting the cart before the horse. The way to conduct risk assessments is to a) decide what you want the answer to be b) come up with something costing a lot of money in order to achieve it.
The desired outcome is that vehicles are enabled to travel as fast as possible. Anything that stands in the way of meeting that objective simply proves the need for more research and design, and more expenditure. Speed is God, so by definition cannot be the cause of anything undesirable.
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