Drafting a big rig

[Bicycle Bob]

So far, it is only on a test track. It may need steering enhancements for long trains to keep them in the lane, and many other enhancements, but it is progress. While it is easiest to deploy in the left lane, most places, it will probably acquire a way for drivers to create gaps for merging or crossing lanes. Even that might be automated by surrounding sensors, breaking trains into short sections as necessary.
The great potential here is to add smart speed controls, without which heavy traffic can't maintain a steady speed. Merging traffic can be neatly added by accelerating beside a "moving" LED display generated to synchronize with the train.

[redneck]

Stay away from trucks period.


I have driven trucks for many years and try to operate them as safely as possible for you and me, this includes keeping a safe distance from all vehicles in the event I have to react to a situation.

If you draft (tailgate) a truck, even though you're behind it, you can cause the driver to pay more attention to you than required, instead of whats in front of them and thats not good for anyone.

The rule to follow is

"If you can't see my mirrors, I can't see you"


Remember...

In order to get respect, you have to give respect.

>

[basjoos]

If you aeromod your car to drop the Cd into the mid 0.10's, then drafting at normal highway speeds offers very minimal mileage benefit. The only use I have for drafting is that it can give me a quick snapshot into how much aeromodding would improve the mileage of whatever I am driving. When drafting, the only thing that has changed is the wind load on your car since engine rpm and rolling resistance remain unchanged. So if your drafting car is experiencing an air speed that half of your ground speed, then the mileage you are getting is the mileage you would be getting without drafting if you cut your Cd in half. Ideally you need an airspeed indicator in the nose of your car to determine airspeed if you want to quantify the drafting mileage benefit. Also the air speed indicator can let you find the best position for drafting and let you know if you were driving into a headwind or tailwind (two other things that a mid 0.10 Cd minimizes the effect of).

Basically the effects of dropping my Cd down to 0.16 is that (compared to the OEM car) it is like I am always driving in a tailwind or in a draft since my aeromods provide the same mileage benefits as drafting or driving in a tailwind without having to do either.

[lowglider]

I don`t draft behind any trucks, but what is it that bothers a trucker if a car drives behind him?
The car˙s headlights can`t bother him because he can`t see them, also he cannot be concerned about safety distance because the car can brake much faster than a truck can.

I`m thinking of this because adaptive cruise controls (automated braking) are now becoming common and it`s quite safe to use them to draft behind trucks and save on fuel.

[Arragonis]

Originally Posted by lowglider

I don`t draft behind any trucks, but what is it that bothers a trucker if a car drives behind him?
The car˙s headlights can`t bother him because he can`t see them, also he cannot be concerned about safety distance because the car can brake much faster than a truck can.

I`m thinking of this because adaptive cruise controls (automated braking) are now becoming common and it`s quite safe to use them to draft behind trucks and save on fuel.

Travelling too close to something in front is dangerous for obvious reasons. Even if you could stop in time there is always the unexpected - in fact everything is unexpected because you can't see. If you pull back abour 5-7 car lengths you get most of the benefit and the truck (or whatever) in front fills less of your vision. If you don't and the truck switches lanes to pass something and you go - bosh.

Truckers also don't like people going too close because they don't want the hassle of an accident - you might be OK but others may not. Plus your lights may not look like they would be bothering the driver but it also may mean he can't see other vehicles passing so its harder for him to judge when he can pull out.

There have been folks on here tapping about truckers switching to the sides to kick up dust and cr@p to discourage tailgaters / drafters.

Plus of course dropping 5 mph or P&G on inclines will gain more and be safer all round.

EDIT : Sorry to be a pooper but I think safety is more important.

[comptiger5000]

As you just said, drafting at a reasonable distance is key. It still gives benefits, but not quite as much. It's a heck of a lot safer though.

[euromodder]

Originally Posted by Bicycle Bob

Here ya go: Robot drafting: Follow the leader: SARTRE road train technology successfully demonstrated

It may sound good in theory, but lets look at the European reality :

You'd be tailing a professional driver. Sounds good, doesn't it ?
In reality, you may very well be drafting an outsourced, often overworked and underpaid new-age slave : an eastern European truck driver without a clue of local traffic regulations.

If he messes up, you'll be messed up, with no chance to intervene - there simply won't be enough time to react.

Check the UN product code over the wireless internet to decide wether you really want to draft that cargo.

Check the shredded rubber on the side of the road.
It usually isn't from a passenger-car, it's too big for that. Way too big.
You could well be drafting a trailer with a few bald tyres about to blow out. Only a few meters ahead of your own car.

What's going to happen if such a train passes an on-ramp to the motorway ?
It'll be pretty hard to get on the motorway.


No thanks !

[colonelk]

interesting thread, and I guess some of my opinions may be swayed not being in the US (I know some europeans have commented)

TBH I follow trucks when on the motorway (I dont draft ) at a set distance. I find it helps me keep a steadier speed, and also seems to make me less of a hazard to other drivers (they see a truck up ahead, they automatically are starting to move over into the middle lane to overtake) rather than assuming Im doing the same 85mph they are (people leave it much later to pull out when there isnt a truck in front of me)

I always thought I was far enough back that I wasnt a problem (a good 4 or 5 car lengths at the very least)

Never had a trucker try to "shake" me. Im at a distance that any stones / etc fall to the ground before they get to me.
If it bugs truckers to have a car close, how come they regularly (and I MEAN regularly) spend their time about 10ft from the truck in front? with another close behind?

Like so....

Very common site in the UK to see a row of 5 or more that close, or very nearly.

I am interested in the lorry tyres ripping off thing. That would obviously be bad, never seen it happen though, and rarely see stripped rubber at the side of the road. Seen plenty with flats / flappy tires, none where they have properly delaminated.

Thing is, people who arent hypermiling (average joes) have to follow trucks all the time on single carriage ways, at speeds upto 60mph, and it doesnt faze them? Are we thinking about this too much?

I dont think theres anyone here who would agree with sitting 10ft off a lorries bumper!

maybe they keep the motorways cleaner in the UK than the states (easier job, theres a heck of a lot less of them!) so the debris thing isnt an issue here (aside from potential delam)

[Arragonis]

Originally Posted by colonelk

I dont think theres anyone here who would agree with sitting 10ft off a lorries bumper!

Lorry's mate, Lorry's

There was a post in here about the lights of their car could not bother a truck because they were so close the truck wouldn't be able to see them

And ShadeTreeMechanic described a scenario where the truck did kick up much to shake him off - or so he thought. I think its in the You Know You're an Ecomodder When... thread. So it has happened.

Not common I grant you.

And yes, truckers should know better.

[RPekka]

Originally Posted by roflwaffle

tap the semi on the rear. Having a safety margin is never a bad idea AFAIK,

Tapping a big rig is not an issue. Just be that far that your front just doesn't cover the brakelights. If you are close enough the rig won't slow down much before the collision so it will be much like bumping a stopped rig at 5 mph. If the rig isn't doing a panic braking you'll be just fine because there is that 1 second delay between the lights going on and the rig starting to slow down.

What makes drafting a big rig dangerous is the stuff coming under the rig or from the rig. A car muffler won't bother the truck driving man but will probably still go thru your car's ac, ic and radiator before splicing the hydraulic lines Retreaded tires can also loose their tread which usually takes the fender around it with it when it leaves and that is about the size of an average car windscreen. That is why I don't draft.