Drafting Behind Trucks: Does it Work?

You mean at ten FEET, you have .124 seconds.... nice post though

LA: Thanks, i have corrected that. Spellcheck doesn't catch that kind of thing!

i have heard of this before but in practice in my experience my car gets that whirlwind effect that blows the car from side to side, turbulence (at about 25 feet away). Does that turbulence hinder the performance or is it part of the test?

I just saw MythBusters do a show on exactly this. You get the best wind reduction at about 10 from the truck, while at 2 feet the driver was on and off the gas so much that it negated the positive effects. You can probably see that via Discovery.com.

This goes good with this month's quote on my "Despair" calendar:

Overconfidence: before you attempt to beat the odds, be sure you can survive the odds beating you.

Please do not do this.If i you can not see my mirrors.I can not see you.If your wish is fuel conservation.Try buying a cat back muffler system and cold air intake/low restriction setup.THIS IS A VERY STUPID STUNT.STAY AWAY.Take a good look at that iron bumper below the doors.

This may just increase the trucker's fuel consumption, so only the car (herinafter referred to as the "potential fatality" or "PF") saves gas.

This may make the slipstream through which the truck drives through more turbulent, increasing the drag on the truck, raising fuel consumption.

I know people who would be stupid enough to drive ten feet off the bumper to save money.

It works for bicycles too. Both riders benefit.

Ditto the stupidity of trying this! Don't do it!

Keep your tires properly inflated, and keep a constant steady speed (at the speed limit!) will save gas. Remove all the unused and unneeded junk in your (car) trunk.

I'm old enough to remember the catch phrase "55 saves lives" but it also saved gas as well!

:)

In the future when cars link together while riding on the expressway using automated computers, this could come in handy,

Look a new way to kill your self!!

So what happens when you're 2 feet away but 1 lane over? Like the 'V' formations birds do.

Ya, the mythbusters episode was full of warnings about how this is very dangerous.

Of course, some place its hard NOT to be withing 100 feet of a semi.

It would be interesting to see if you could design trucks to allow drafting behind them at a safe distance (150ft +) without sacrificing the trucks gas milage.

Another idea would be to have a screen on the back of the truck showing what the driver is seeing so you can get some warning if the truck is going to suddenly stop or slow down.

Actually, 2 feet behind the bumper, driving 55 mph behind a truck who can't see me sounds like a PERFECT way to save a ton of money at the fuel pump.

Just think - after that trucker taps his brakes just one time, I'll have totaled my car. See? No car, no need to buy gas!

Think I'll stick with my Prius, with it's nifty thrifty 0.26 drag coefficient.

Bredlo no car would not be the problem.No life would be the problem.That i beam bumper would slice you in half.

please be careful on the roadways. i love good mpg. i own a prius. but please don't drive in big trucks blind spots. even the picture was taken in the drivers blind spot, so the driver doesn't know you are there.

always drive so that you can see the mirrors of someone in a big truck. please be careful on the roadways!

As the safety director for our trucking company I would have to agree. Do not tailgate trucks. This a newly named (Hypermiling) old idea of drafting and is very unsafe for all on our nations highways. As far as saving a few dollars on fuel, come up with a safer and better Idea. In the trucking industry most if not all company's have implemented a fuel surcharge to compensate for the higher cost of fuel. I would much rather have my drivers return home to there familys safetly than save a few dollars in fuel.

Good luck and be safe.

Actually 1.2 seconds to respond, is plenty of time. You are going to stop about 4x faster than the truck can. If someone can't react in under 1 second they shouldn't be driving.

I draft all the time, in the winter, you always hear of 50 or 100 car pile ups so if there's an accident it doesn't matter much if your'e 100 ft back or 10 ft

most OPP drivers follow trucks in the passing lane by about 3 ft

just remember if a car cuts you off and you swerve to avoid it, you're at fault if the only thing you hit is a guard-rail so it's better to not let anyone get in front of you

And when you are ten feet off of the truckers bumper what do you think will happen when (not if) he throws a tread off of his tire. Ouch!

I have heard the argument that the trucker won't know if your car is small enough but then there are things called CB radios and other trucker's telling him about you.

If you want to save 45% more fuel just drive slower, switch to a really efficent car for your needs and stay home more.

Invite your friends over for dinner and board games or something...

As a truck driver may I ask your readers, PLEASE DON'T TAILGATE TRUCKS! It not only drives us crazy, being a very annoying habit by 'four-wheelers', but it is one of the most dangerous things you can do. So close behind a truck you cannot possibly see what's up ahead, and if I stop my truck, or even suddenly slow down for any reason... YOU ARE DEAD! On the freeway, you get so close behind me, and, other traffic allowing, I will slow down to the point where you are forced to pass me. Won't put up with it. Not no way, not nohow! Find a better way to save gas, please, for your own safety!!

Just hitch your car to the back of the truck and save 100% on gas, sounds good to me.

To all my good buddy truckers: Please pay attention to the traffic in front of you and beside you. You have a vehicle that ways over a dozen tons and if you aren't doing your job professionally, you have the real potential to take human life.

If me, in my compact car, decide to follow you at around 75' or so (just a bit further back than that picture ... still in your blind spot), it is nothing YOU need to be concerned with.

The day I cannot out-break a tractor trailer with my efficient little car, you can have my keys ... and plant me in the ground, while you're at it.

And, if I REALLY blow it, and somehow end up hitting the back of your truck, your main concern is straightening out your license frame bracket before driving on. That's about it.

Really, get over it.

This has to be the most ignorant ( or is that selfish? ) trick I've ever heard. I'm the wife of a 'professional' driver. Let me tell you, that WHEN, not IF he hits the brakes to avoid a road hazard or another vehicle in his path ( likely that same 4-wheeler who just cut you off to jump in front of that 80,000#+ fast moving vehicle ), he will NOT be responsible for your death, which WILL in fact occur. However, I do know that MY husband would then blame himself forever for not avoiding your death any way he could. Wouldn't matter you were the stupid one, he still values life over money. Doesn't anyone else value life anymore? Not even their own? Good grief people, get real here. How much gas are you really saving, to risk not only your life, but that of the trucker and the other 4-wheelers behind, beside, and in front of you? Mere pennies? That's right. There are laws written and enforced regarding this practice. Please don't put MY husband's life at risk to save your pennies. You see, he's just like you, he's out there trying to make a living and support his family. Go get a second job flipping burgers for God's sake!! Or better yet, stay home and out of his way entirely while he does what he does best, bring you all the things you are hurrying to Wal-Mart to buy because you just HAVE to have IT right now and need to save pennies to be able to afford IT. Stay home! Conserve your gas and be sensible about your travel. There are dozens of ways to save your pennies. Again, I say do NOT put humanity at risk for your stupid so-called 'hypermiling' tricks. Hyper mile your way right back into your garage and leave it there. My husband, and millions of other truckers, AND their wives and families will thank you.

To the commenter who asked about the buffeting side to side - you felt that because you weren't close enough yet to benefit from the drafting. You have to be closer.

And yet, you were already pretty darn close, weren't you?

Let me tell you from my motorcycing experience -- the forces of a draft are powerful. The forces of inertia in a crash are more powerful still.

Just not worth it...

i remember watching this episode of mythbusters...

the sad thing is that while it is dangerous, its not just as simple as "you have this or this" because for starters the difference between a loaded truck and an unloaded truck are so vast... coupled with the fact that 1.25 is just the reaction time at 100 feet, most people have a fair reaction time (yeah, stay the hell off your phone and dont get too damn close) and all you have to do is slow down... your car slows down a HELL of a lot faster than that loaded truck does... another is this is all dependant on the fact that most people are in too much of a hurry to actually match up behind a trucker following the speed limit anyway...

bottom line, yeah... it works... is it dangerous...yeah? should you do it? technically no, but if you're going to do it you're probably gonna do it whether anyone says anything or not... just be safer, stay beyond the 1 second zone and make sure you do the following...

1>be ALERT (no damn cellphones)
2>wear it... (its the law, yeah...but trust me damnit... seatbelts work)
3>make sure your brakes and tires are good... you have a second to slow down, make sure the gear is up to the task

So why wasnt this test done at the safe distance? I try to follow the two second rule on the highway, but if I can do it behind a semi, I'll go for it. Why not find a truck that's not travelling at break neck speed and just sit safely behind 'em. Also, it sounds to me like the "bumpers" just aren't adequate on these trucks. If a rear end collision is so dangerous, why are these allowed? I'm reading some high and mighty posts, but I've been tailgated by semis a lot more than the other way around. How about the danger to MY life if I get rear ended by a semi? Seems a little different than the risk to a truck driver if I rear end them. Am I actually going to shove them off the road with my compact?

I loved the hysterical response to my post above. Following trucks at 50'-70' threatens humanity? Puhleeze!

Mythbusters showed drafting at many distances (results available on Wikipedia). 10' back was the best ... but dangerous. 75' distance still had some benefit and I believe they said it was 'safe.'

People like myself that follow trucks at a 'reasonable' distance (my estimate) are usually very careful, conscientous drivers and are not a threat to anyone.

However, as was pointed out, semi-drivers that tailgate kill hundreds, maybe THOUSANDS in this country every year.

Let's not lose all perspective to ignorance, myths and hysterics.

It's a lose-lose situation.
The buffeting wind when following a truck farther back isn't worth it, and the concentration required when following so closely you aren't buffeted isn't worth the stress.
There are better ways of hypermiling.
And some of you are correct, truckers tailgaiting are far more of a threat then drafters.

What I'm reading here doesn't entirely add up.

A car tailgating is dangerous because the truck driver can't see him? Pfft... the trucker needs to keep an eye on the car/truck that's in front of him that HE'S tailgating.

If a truck throws a tread, is it more dangerous to be closer or a bit further back?

Well if I'm closer, the tread won't have had a chance to have slowed down enough for there to be a big difference in speed to cause as much damage.

But if I hit that same piece of tread while it is standing still, my knowledge of physics tells me that it'll do much more damage.

Same situation if the truck loses a wheel. Actually, a lost wheel is most dangerous to oncoming traffic since it could potentially bounce to the other side of the road and through the windshield of any car OR truck.

And in the case of ice falling off the roof of the trailer... I've seen that happen many times and from experience I can say that the two best places to avoid that is to either be close behind so it goes over you or faaaar behind. Being about 2 seconds behind is the perfect place to get hit by ice it seems.

On the subject of braking... EVERY truck I've seen brake hard - loaded or unloaded - brakes slower than a well maintained car with decent tires. I've also heard many truckers say you shouldn't cut off trucks because trucks can't brake as fast.

So what gives?

Someone shouldn't go in front of a truck because "they can't brake as fast", but if the person follows behind, now all of a sudden trucks now have super-brakes and can now stop better than the best sports cars?

Oh please.

As a matter of fact, I've driven vehicles with trailers with trailer brakes... and you know what? I found that vehicles with trailers - even when equipped with trailer brakes - DON'T stop as quickly as a well maintained car even when the trailer is empty.

So what I'm getting at is that I keep hearing truckers talking about all the dangers of us tailgaiting them (but of course those dangers don't exist when they tailgait other cars or trucks), but I've only heard two actual specific dangers that I've just debunked.

Trucks DON'T brake as well and if there's road debris, in the greater scheme of things, being close to a truck doesn't make much of a difference... with the exception of having more dirt/rocks kicked up onto your car if the truck driver decides to be an asshole and deliberately go on the shoulder a bit...

Actually in the case of having a moose/deer run across the highway, I'd say that it would actually be safer to be behind a big truck since it would be better for me for the truck to hit it than for me to hit it... even if pieces of the moose end up going between all the wheels.

The only real danger is the danger of rear ending them... but that applies to tailgating any vehicle.

I would say it is FAR more dangerous to be BESIDE or IN FRONT of a big truck. If the truck loses a wheel, you'll get hit. If the truck tips, it'll be to the side on a curve and you'll get crushed. If the trucker needs to swerve, you'll get crushed. And if you stand on the brakes, the truck runs into you and you get crushed.

Being behind a truck means you might kill yourself if you're not paying attention and didn't hit the brakes hard/fast enough. But if you're not paying attention, you're putting yourself at risk no matter what the situation is.

Feel free to disagree... but then provide some actual specifics rather than vague statements and allusions to danger.

Sidenote: I personally only tried tailgating/drafting as an experiment... but I don't do this as I prefer to just stay in the right lane with the cruise-control set to 10KM or so under the speed limit and have a more relaxing drive and also not piss off truckers.

"Feel free to disagree... but then provide some actual specifics rather than vague statements and allusions to danger."

>>> okay, i'll give it a shot...

What I'm reading here doesn't entirely add up.

A car tailgating is dangerous because the truck driver can't see him? Pfft... the trucker needs to keep an eye on the car/truck that's in front of him that HE'S tailgating.

>>> truck drivers aren't the enemy here. it takes a while to change lanes in a truck, and if the driver can't see you he can't tell that you are about to whip out and around him while he is maneuvering.

If a truck throws a tread, is it more dangerous to be closer or a bit further back?

>>> personally, i'd rather be farther back so that I could see it coming. more time to avoid it.

Well if I'm closer, the tread won't have had a chance to have slowed down enough for there to be a big difference in speed to cause as much damage.

>>> incorrect. most of the tread will come off behind the tire and will be at or close to the speed of the pavement (0mph) , not the speed of the truck. if a truck is travelling at 60mph, the bottom of the tire is at 0mph (as it is in contact with the road) and the top of the tire is at 120mph.

But if I hit that same piece of tread while it is standing still, my knowledge of physics tells me that it'll do much more damage.

>>> yep

Same situation if the truck loses a wheel. Actually, a lost wheel is most dangerous to oncoming traffic since it could potentially bounce to the other side of the road and through the windshield of any car OR truck.

>>> good luck seeing the wheel if you are right behind him. good luck if you run over a thrown truck wheel in the average passenger car.

And in the case of ice falling off the roof of the trailer... I've seen that happen many times and from experience I can say that the two best places to avoid that is to either be close behind so it goes over you or faaaar behind. Being about 2 seconds behind is the perfect place to get hit by ice it seems.

>>> I would have to agree with you on this one

On the subject of braking... EVERY truck I've seen brake hard - loaded or unloaded - brakes slower than a well maintained car with decent tires. I've also heard many truckers say you shouldn't cut off trucks because trucks can't brake as fast.

>>> Braking distance has little to do with the danger of following too close. Mostly it's reaction time that does you in. If you happen to be completely focused on the vehicle, and brake immediately and sufficiently enough, you will likely stop before the truck does. Now add cell phones, fast food, passenger conversation, distractions of any kind, and your 1-2 second advantage is gone.

So what gives?

Someone shouldn't go in front of a truck because "they can't brake as fast", but if the person follows behind, now all of a sudden trucks now have super-brakes and can now stop better than the best sports cars?

>>> see above

Oh please.

>>> okay, PLEASE see above

As a matter of fact, I've driven vehicles with trailers with trailer brakes... and you know what? I found that vehicles with trailers - even when equipped with trailer brakes - DON'T stop as quickly as a well maintained car even when the trailer is empty.

>>> I drove a ford F-450 utility body truck that, when fully loaded whieghed 12-13k. It also had 14" hydraulic discs on all axles. It was a dually, and so had 6 tires. braking has a great deal to do with how much tire is in contact with the road, and how much wieght is on each tire. That truck would go from 60 to 0 in a shorter distance than most cars I have owned or driven.

So what I'm getting at is that I keep hearing truckers talking about all the dangers of us tailgaiting them (but of course those dangers don't exist when they tailgait other cars or trucks), but I've only heard two actual specific dangers that I've just debunked.

>>> the dangers exist for the trucks who tailgate as well.

Trucks DON'T brake as well and if there's road debris, in the greater scheme of things, being close to a truck doesn't make much of a difference... with the exception of having more dirt/rocks kicked up onto your car if the truck driver decides to be an asshole and deliberately go on the shoulder a bit...

>>> truck drivers can't swerve to avoid road debris nearly as well as small car drives. if a truck driver sees a tire in the road, or anything small enough to fit under the truck (cooler, lawn chair, ladder, wooden pallet, couch cushion, mattress, etc., etc., ) he is going to drive right over it. if you are right on his tail, you will not have time to react. your car does not have near the ground clearance that the truck does. have you ever driven over a ladder at 60mph?
- or how about this one... truck at 60, you right on his ass. he comes up quick on a braking vehicle, decides he has no room to brake, looks in the mirror and sees that he has just enough room to jump into the next lane. you see him swerve, look left and can't get over because of the car that the truck just cut off, and by the time you look up you just paid for a new boat for the idiot going 42 on the freeway.

Actually in the case of having a moose/deer run across the highway, I'd say that it would actually be safer to be behind a big truck since it would be better for me for the truck to hit it than for me to hit it... even if pieces of the moose end up going between all the wheels.

>>> personally, i'd rather know it was coming

The only real danger is the danger of rear ending them... but that applies to tailgating any vehicle.

>>> yep

I would say it is FAR more dangerous to be BESIDE or IN FRONT of a big truck. If the truck loses a wheel, you'll get hit. If the truck tips, it'll be to the side on a curve and you'll get crushed. If the trucker needs to swerve, you'll get crushed. And if you stand on the brakes, the truck runs into you and you get crushed.

>>> ummmm....

Being behind a truck means you might kill yourself if you're not paying attention and didn't hit the brakes hard/fast enough. But if you're not paying attention, you're putting yourself at risk no matter what the situation is.

>>> yep

Sidenote: I personally only tried tailgating/drafting as an experiment... but I don't do this as I prefer to just stay in the right lane with the cruise-control set to 10KM or so under the speed limit and have a more relaxing drive and also not piss off truckers.

>>> oh, so you are the guy with the boat? why not travel at or near the limit, which is what we are all expecting......

This is, of course, just my take on the subjects above. I have a commercial DL. I have driven everything from a motorcycle to a full tractor trailer in nearly every state in the country and in 5 foriegn countries. I have seen accidents. I have been in accidents. I have caused accidents. The older I get, the more careful I become.

The following are the best ways to get max mileage out of whatever you are driving---regardless of your driving style.
1.Keep tires at max recommended pressure.
2.Regular tune-ups and oil changes
3.Windows and/or convertible top UP
4.Air conditioner off (nearly 20% difference in fuel mileage on my wifes toyoto avalon!!!)

-I follow the first to religiously... the last one is out of the question here in florida

Also-

Install aftermaket cat-back exhaust and cold air intake system. The same technology that increases horsepower for the racers increases effeciency for the greenies. Car manufacturers are bound by noise restrictions when designing intake/exhaust systems. The insane convoluted routing that the air must take to get from the front of the car into the combustion chamber is designed to limit noise. Same on the exhaust side. Make the swap and enjoy a few more miles out of each costly gallon. The extra punch comes in handy from time to time, as well.

Just remember the two second rule you learned in defensive driving.

Also, remember that, at 55mph, two seconds is 161 feet. This is still within the draft zone.

Peter's responses to Randall are right on. The only thing I would add is that a blown tire often leaves a cloud of debris, sometimes including mud flap bracket parts. Such an incident killed 6 children in a following minivan that caught on fire, and resulted in a multi-million dollar law suit. Once you have seen it happen, I doubt you would ever follow that close. Another incident (that I witnessed) involved two elderly people in a Buick, totally lost in zero visibility from a cloud of dirt, tire parts and who knows what else. Luckily the driver had the presence of mind to gradually slow without any sudden steering input.
I can't say never allow your car to hit pieces of truck tire (what truckers call "gators") but make sure you only do so if there are no other safe choices. They can cause heavy damage/further accident potential.
Also consider "deer whistles", available at most truck stops/travel centers. Out of thousands of deer I've seen on the roads, I only hit one (he was already dead and didn't respond to the whistle).

So all you people seem to think a large truck can stop on a dime and wont give you any time to react? Have you ever seen a trucker slam on his brakes? he doesnt slow down .. just a large puff of smoke as all his tires lock up.At 30 feet you have time to react.. The main problem in road hazards, like large debris in the road.

If a truck slams on its brakes it takes a hell of a lot longer to stop than your car.

Everyone that agrees to follow too close behind a semi or any vehicle for that matter, are IDIOTS! You are seriously putting your lives and other people lives in danger. In no way, shape, or form should you EVER follow too close behind any vehicle. As for all of you knuckleheads, who say that a car can stop quicker than a semi has lost their noggins! Ok, maybe a car can stop faster than a semi, BUT, Y?, Y?, Y? would you test the limits?! In one incident, I was not even following a semi as close as you are allowing for this so called "draft". I was in a brand new (2007) vehicle, tires, etc. I could not see in front of the semi, therefore not knowing that the vehicle in front of the semi had come to a complete halt in the middle of a street where there are no turns! At this point, the semi wheels locked to avoid hitting the vehicle and bcuz i couldn't see past the semi to realize what was going on, i immediately had to slam on brakes. Because this gesture of movement was too quick for my car to react, MY wheels also locked! I almost slid right into the rails/bumper of the semi. I had to swerve into the other lane, still sliding to avoid a potentially deadly situation. Guess how fast we were going?! ........45 mph!! And let me tell you, I never again want to look at another semis bumper/rails and see my life flash before my lives. So if you think this is perfectly safe because you trust that your little car will stop on the dime, then have at it! I just will be the A Hole that passes you in the left lane and shake my head and say "look at that moron trying to save a buck". "Pathetic"!

Just let me say first off, No way should a 4-wheeler(cars) nor a semi ever tailgate any one! This practice is very dangerous and probably makes up of most preventable accidents. Now having said that.

Will: The reason big trucks have DOT bumpers is because this is to help prevent a truck backing up to a dock from backing thru the dock. It is also used for more visibilty to aware the public of the back of the trailor. (hence red/white reflector tape on the bumper) And the best of all, it is used to prevent a tailing vehicle, that may rear end a truck, from sliding through the tandems (wheel axles) and further under the trailer, decapatating off your head and your passenger's heads. If a truck did not have these bumpers, a vehicle would probably slide into and damage the tandems. (Which by the way, a trailer is very sensitive to touch, being that it is top heavy and would probably rollover, like any other tall, top, heavy objects that if they are hit from the bottom, would topple over). So the reason for the bumpers? DOT would rather the tailgator, who rearended the truck, to have a horrible death than the innocent bystanders on the side and n front of the truck who had enough sense not to Tailgate!

To Adam, My Good Buddy 4-wheeler; If you are not already dead, please pay close attention to this post! If you would have listened in your small little driver's ed course, you would have known that when you are driving, you are supposed to pay attention to ALL of your surroundings. This means, in front of you, on the side of you, and also BEHIND you. So this means that, I, a professional truck driver, who has way more education and experience in driving than you do, will pay attention to ALL of my surroundings. Because I am a professional driver(hence should I say a "professional" again), I must not only drive/watch out for the safety of myself, but I should also drive/watch out for the safety of the public. (hence you) So with that said, I just want to alert you that I drive over a "dozen ton" tractor-trailer tanker. And in that trailer/tanker is hazardous materials that can either be flammable, combustible, or corrosive. So when your little compact car decides that it wants to follow me around 75' or so, it is something that I would most definetly be concerned with and you should be too. Because the day WHEN, (if you keep on driving this dangerous) something happens to where you cannot out brake a tractor-trailer with your "efficient little car", I will not need your keys and i will not have to plant you in the ground. When that tank blows up, with you first, being that you ran into it, and then me and everyone else around it, our loved ones will be planting us all into the ground! (6 feet deep that is) So No. My main concern would not be straightening out my license frame bucket before driving off. It would be how would they be able to tell my melted license frame bucket apart from your melted car! Yea I know you are probably saying that you might not do this to tankers, but that's the thing. You cannot see in these trailers, so you have no idea what a trucker might be hauling that can harm you if ignited. You know this is what is wrong with the driving public today. They really have people that don't use common sense, they are not educated enough, or they just really don't care.