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PostPosted: Mon Feb 05, 2007 23:58 
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I found out yesterday that a good friend of mine is in the habit of slipstreaming behind artics on the motorway because it's the only way that his under-powered camper van and trailer will get over 50 mph. For this to work he has to be extremely close, ten feet or so off the rear bumper of the truck. It sounds quite dangerous to me, but he claims that it's actually reasonably safe because a heavily loaded artic has very little braking available and his camper will comfortably out-brake it. Setting aside how certain you can be that the truck you're tailgating is fully loaded, and the obvious stupidity of getting that close to *anything* at high speed, I'm curious to know whether he's right about the truck brakes. I'd like to think that even a fully loaded forty tonner can pull somewhere in the region of 1G under braking if necessary. Any experts here know?

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PostPosted: Tue Feb 06, 2007 02:41 
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I wouldn't think a fully loaded artic would get anywhere near 1g braking; but nonetheless would probably be able to brake as fast as a camper van, let alone one towing a (no doubt unbraked) trailer.

I'd say your mate is an idiot! I have a moderate sized trailer that I use a fair bit for transporting building materials, firewood etc, and I look to maintain longer gaps in traffic than I normally would, as I have less cornering and less braking capability. Tailgating is out of the question as I need to see what the lorry is seeing, not the back of his bumper!

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PostPosted: Tue Feb 06, 2007 09:40 
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Two points.

Trucks have exhaust brakes that slow the vehicle without lighting the brake lights (used on long downhills to maintain speed without cooking the wheel brakes). They aren't designed for decelleration as such but will slow the vehicle gradually.

Gear changes. If he's gating up a hill and the truck driver has to change gear he's screwed. It takes much longer to change gear in a truck than in a car and the loss of forward speed can be significant.

Aside from that, if he's that close to the back of an artic the artic driver will NOT be able to see him in his mirrors, and your friend won't be able to see past the artic for any hazards ahead.

Then there's the problem of joining traffic possibly not seeing him for whatever reason...

Generally I'd agree with JT, its a bloody stupid idea.

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PostPosted: Tue Feb 06, 2007 11:46 
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Oh I agree absolutely, it's bl**dy stupid for lots of reasons. But can anyone tell me what sort of deceleration a fully loaded artic can achieve under braking?

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PostPosted: Tue Feb 06, 2007 12:19 
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greenv8s wrote:
Oh I agree absolutely, it's bl**dy stupid for lots of reasons. But can anyone tell me what sort of deceleration a fully loaded artic can achieve under braking?


I drive them. Enough braking that he won't have time to react. They don't slow that quickly but in an emergency probably as fast as his camper with the trailer.How does he know it's fully loaded? You can't tell from the outside.
Almost all artics and trailers have ABS now so at speed maybe even faster depending on what the camper is.
If it's a VW then he hasn't got a hope in hell.He might as well have his legs amputated now to save the docs having to do it to get him out of the wreck.

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PostPosted: Tue Feb 06, 2007 13:23 
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if its a volvo, he has no chance. a volvo pulling an empty trailer will deccellerate sharp enough to throw the driver forward and that is WITHOUT touching the brakes (so no lights). they have the best exhaust brakes in the business. with brakes used too, the stopping distance will be surprisingly short. even fully laden at 44 tonnes, a volvo with a decent condition trailer would surprise you. see this thread
http://www.safespeed.org.uk/forum/viewtopic.php?t=6730

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PostPosted: Tue Feb 06, 2007 14:26 
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There's more to it than brake efficiency. What is your friend planning to do if the truck in front hits something, or gets a blow-out?


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PostPosted: Sun Sep 02, 2007 15:42 
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scanny77 wrote:
if its a volvo, he has no chance. a volvo pulling an empty trailer will deccellerate sharp enough to throw the driver forward and that is WITHOUT touching the brakes (so no lights). they have the best exhaust brakes in the business.
http://www.safespeed.org.uk/forum/viewtopic.php?t=6730


All volvos since august 2007 now operate the brake lights when using full retardation on the column stalk exhaust brake , possibly due to this reason ?

as for the camper van , bet he hasent been close enough yet when the driver has forgot to connect the electric souzie ( = no lights at all working on the trailer)


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PostPosted: Sun Sep 02, 2007 16:21 
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Makes me wonder how he can even get close to a truck if he otherwise can’t maintain 50.

Anyway, every time the truck’s brake lights come on (for any reason), he will have to apply full anchors to minimise (not eliminate) the possibility of shunting should the truck brake hard – that doesn’t sound safe to me.

Assuming the truck could decelerate at 0.7G, the campervan could decelerate at 0.9G and the driver has a reaction time of 0.5 seconds (that’s very generous) and had left an initial gap of 3.3 meters, a quick excel spreadsheet shows that they will collide 1.45 seconds after the truck starts to brake – even though the campervan can outbrake the truck.

It’s not just idiotic - it’s dangerous.

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PostPosted: Sun Sep 02, 2007 17:00 
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even better, what if another HGV is gaining slowly on the camper van , getting ready to make his overtaking move ?

firstly, the camper has now made it a longer distance for the 2nd HGV to have to cover before he can get back into lane 1 , causing furtehr delays for any cars already trying to pass.

secondly , if the 1st HGv stops ( lights or not) , and the camper does react within micro seconds, what if the 2nd HGV doesnt ? = Game Over .
44 ton block-> camper <- 44 ton block sandwich ..................


if the camper is not capable of driving at 50mph, it SHOULDNT even be on a motorway IMO
the camper driver is a clown im afraid


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PostPosted: Tue Sep 04, 2007 08:48 
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volvofl10 wrote:
as for the camper van , bet he hasent been close enough yet when the driver has forgot to connect the electric souzie ( = no lights at all working on the trailer)


or the line has been broken. i have pulled a wagon over on the M27 to warn him of his lack of brake lights. the head was broken off one of his lines during a delivery. he hadnt noticed

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PostPosted: Wed Oct 31, 2007 20:08 
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Fully loaded with what ?

If it's pallets of a product that are not all gonna end up on the headboard then we can brake pretty damn hard.

It's the "reaction time" thats the problem... This is the primary reason a truck driver sits high above the regular traffic.

Trust me... If your mate is sitting up my ringpiece I can assure you he'll almost certainly have heart failure before leg failure (impact) if I am forced to throw the anchor out the window when driving MY truck

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PostPosted: Wed Nov 14, 2007 21:29 
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greenv8s wrote:
Oh I agree absolutely, it's bl**dy stupid for lots of reasons. But can anyone tell me what sort of deceleration a fully loaded artic can achieve under braking?


shouldnt you be more concerned about the empty ones? a light artic will stop rather sharpish compared to a fully freighted 44 tonner. from the back you just cant tell unless its an open trailer. take my iceland wagon. looking at it you cant tell if im loaded or empty. you dont know if im heading out to the shops or heading back in. tailing an artic is not a good idea under any circumstances

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PostPosted: Tue Apr 29, 2008 13:16 
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greenv8s wrote:
Oh I agree absolutely, it's bl**dy stupid for lots of reasons. But can anyone tell me what sort of deceleration a fully loaded artic can achieve under braking?


A truck in good condition with evenly distributed load on a good surface can stop almost as quickly and efficiently as the average family car and quicker than some of the weighty vans/campers etc, if not then there would be two overall stopping distances listed in the highway code.

Tailgating is a huge problem no matter where you go and it is impossible to get through to people how stupid it is. There is ZERO advantage in driving too close to the vehicle in front and I have yet to meet someone who can show me one ( dont go off at a tangeant and talk about racing ok.)People even use the excuse that they are keeping up with flow of traffic :roll: more like sheep keeping up with the sheep in front. The most stupid thing about those who tailgate is that by doing so 50% or more people would slow down just to annoy the tailgater. :lol:


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PostPosted: Tue Apr 29, 2008 17:11 
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Herbie J wrote:
50% or more people would slow down just to annoy the tailgater. :lol:


:hello:

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PostPosted: Wed Apr 30, 2008 09:34 
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No, no, no, you don't slow down to annoy the tailgater, you slow down until the gap they've left is appropriate for the speed you're doing! :twisted:

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PostPosted: Sat Jun 21, 2008 20:24 
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Sixy_the_red wrote:
No, no, no, you don't slow down to annoy the tailgater, you slow down until the gap they've left is appropriate for the speed you're doing! :twisted:


Friend of mine got done 400 quid for tailgating, dont slow down too much 'sixty' , you might give them a chance to pass, Id rather encourage the loss of 400 quid :lol:


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PostPosted: Sun Jun 22, 2008 09:43 
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I'd rather avoid being rammed by them by getting them to f*ck off! :)

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