A question for the lorry drivers amongst us

[Spinney]

Driving on the motorway, most folks (including me some of the time ) drive too close to the vehicle in front. But when passing lorries it often seems as if there is only a few feet between the back of one and the cab of the next. How do they expect to stop in time if the lorry in front has to brake suddenly? From their driving position, they surely can't see past the truck in front? And they are professional drivers.

What's going on? Is there something about driving lorries that makes them different to other vehicles?

(I'm not saying all lorry drivers do this, and I'm not trying to get at anyone, I am really just wondering about why they do it!)

 

[Mark1978]

Im not a lorry driver, but im guessing that they find the reduction in wind resistance beneficial to their fuel usage figures. Its just like a lorry peleton.

 

[helston90]

They're probably drafting each other- if you're weighing 10's of tonnes with a flat front like that and have a few hundred miles to do you can save a fortune through a good draft.

 

[KEEF]

They're probably drafting each other- if you're weighing 10's of tonnes with a flat front like that and have a few hundred miles to do you can save a fortune through a good draft.

Sorry that's complete tosh they are fecking idiots and I am a driver. They will find out the error of their ways when they have to apply the brakes in a hurry.

 

[PeteXXX]

EU regs limit the speed of all lorries to approximately the same, ie 56 mph. Top speed variation is usually determined by the power of the lorry, payload weight and gradient.
I drive motorways @ 52 mph to get better fuel figures. I'm not in a rush like lots of drivers. Anyway, after a few hours, at 52, the 56 mph truck is only about 8 miles in front.. Approx. 10 minutes.
BTW, As soon as I leave a gap in front of me, someone pops into it (car, van or truck) and takes away my braking space.

But, in answer to the OP, No, I don't understand why drivers leave such a minute gap. Stupidity personified!

 

[Globalti]

When I was much much younger I got a staff agency job driving 3 tonners. The throttle pedal was so stiff that it made my leg ache. Quite soon I discovered a piece of foam in the cab that, judging from the crease marks, the permanent driver was in the habit of folding in four and wedging between his knee and the dashboard, so I used to belt along with the truck firmly stuck at full throttle and no chance of reacting fast to an emergency. I also seemed to be passing all the other trucks on the A road I used and it wasn't until months later that I discovered that trucks have different speed limits on A roads.....

 

[Mark1978]

Sorry that's complete tosh they are fecking idiots and I am a driver. They will find out the error of their ways when they have to apply the brakes in a hurry.

Just like in the peleton

 

[Brandane]

Im not a lorry driver, but im guessing that they find the reduction in wind resistance beneficial to their fuel usage figures. Its just like a lorry peleton.

I am a driver but I don't pay for the fuel, therefore in all honesty I couldn't give a monkeys how much it uses. My priority is the safety of my vehicle, its load, and that of myself and other road users.
The problem arises because of the speed limiters all being set at 55mph, give or take the odd exception (e.g. Tesco run their lorrys at 50mph). This causes bunching, and is also why lorries tend to be slow at overtaking each other. This is also the reason why they tend to close up on each other rather than pulling out earlier and prolonging the overtake.

 

[Spinney]

I am a driver but I don't pay for the fuel, therefore in all honesty I couldn't give a monkeys how much it uses. My priority is the safety of my vehicle, its load, and that of myself and other road users.
The problem arises because of the speed limiters all being set at 55mph, give or take the odd exception (e.g. Tesco run their lorrys at 50mph). This causes bunching, and is also why lorries tend to be slow at overtaking each other. This is also the reason why they tend to close up on each other rather than pulling out earlier and prolonging the overtake.

But they seem to do this even in 40 mph roadworks on the motorway etc.

And I really don't like it when I look in my rear view mirror and all I can see is a lorry's radiator grille!

 

[Trevor_P]

I'm always incredulous at this as a Thirty year truck driver, or wagon driver as we like to say over here.

Many car drivers will have heard of the two second rule I hope. i. e. Leave a minimum two seconds gap between you and the vehicle in front. For wagons, the similar rule used to be five seconds or there abouts. My wagon is limited to 51.5 which suits me fine. I leave a minimum 70m gap, but usually 100m on motorways.

It's usually those that can't be bothered to back off the cruise control who tailgate, ready for an overtake. They, can't pull out early because it takes too long to complete the manoeuvre and some numpty will undertake them. Which is of course not in the highway code, nor safe.

People often jump in the gap I leave, including other wagon drivers. I just back off and maintain a safe distance. TBH this doesn't have much of an effect on driving time at all. At some point there's a queue and any gains the tailgaters have made are lost.

 

[swansonj]

I seem to remember it was an exchange along those lines that led to @swansonj's sig line .

'Twas indeed. It is, however, possible that between my writing of my post and your reading of it, there was a miscommunication as to the degree of drafting I engage in. You may have had a vision of my glueing my nose to the tailgate of a lorry. I will willingly admit that, on roads where I can see enough to judge that the risk of the lorry stoping suddenly is at the low end of the scale, I encroach on the "stop in the distance you can see to be clear" zone in the interests of fuel economy; but I encroach to an extent that is a calculated risk assessment, not suicidal. And all of driving is a calculated risk assessment, isn't it?

If lorry drivers are bothered by fuel consumption, why do they drive at constant speed regardless of gradient? In my pursuit of fuel economy, I slow down up hills; I'm quite happy to let my speed on a motorway on a long up hill drop to 40. But lorries steam up the hills on their speed-limited 56 mph, which must ruin any concern about mpg. They get quite pissed off with me if they are still overtaking me when I reach the top of the hill and start accelerating again.

 

[w00hoo_kent]

Why does being limited to 55mph cause bunching? Are they not able to slow down?

Judging by the times I've used cruise control in the car driving at 56mph means you'll slow as you hit a gradient then speed up again, as you slow the lorry behind will catch and then get the draft and speed up with you. Over distance they close together. I guess when you're driving across Europe hour after hour it gets easy to adopt lazy, less safe driving methods. So once you know you're all at top speed you just sit there.

That or they all watched Convoy repeatedly and are emulating their heroes.

 

[Brandane]

Why does being limited to 55mph cause bunching? Are they not able to slow down?

It would seem some aren't.

 

[KEEF]

Modern trucks have mainly auto gearboxes and engines with lots of horsepower (400 upwards) delivered in a very narrow rev band which comes in at the limited speed limit which optimizes fuel consumption and emissions.Tailgating has nothing to do with this or limiters drafting or any other theory, they are impatient idiots who will not back of one mph, they would rather risk life and limb sitting up the next trucks arse or taking 10 mile to overtake it to arrive at their destination 10 minutes in front of the truck behind. Most truck manufacturers offer training in how to drive these modern machines but it doesn't work believe me The clock wins every time.

 

[Brandane]

Judging by the times I've used cruise control in the car driving at 56mph means you'll slow as you hit a gradient then speed up again, as you slow the lorry behind will catch and then get the draft and speed up with you. Over distance they close together. I guess when you're driving across Europe hour after hour it gets easy to adopt lazy, less safe driving methods. So once you know you're all at top speed you just sit there.

That or they all watched Convoy repeatedly and are emulating their heroes.

This will depend on the weight of your load. A fully laden artic with a maximum gross weight of 44 tonnes will struggle up a long steep gradient, despite its 480 or thereabouts bhp. Run the same lorry on the same gradient with a light load or even empty, and it will breeze up it without dropping a gear.
I would suggest your car is under-powered.