Traveling in truck's wake to boost MPG?
 

While driving on an interstate, how far behind an 18-wheeler should I safely travel in order to reap the MPG benefits of traveling in the truck's wake? Is the resultant MPG boost worth taking the time to do this, or is it negligible?

I remember seeing something like this 'tested' on Mythbusters. The conclusion, if I am not mistaken, was that you only benefitted significantly if you were about a metre from the back of the truck—you save on fuel, but lose out on life expectancy. Above that distance, the effects are almost imperceptible.

(I add that when on my scooter, there is a definite benefit even at a safe distance. I think it's the more upright profile compared to a car, as well as the greatly decreased weight.)

The closer you will go to the truck, the better MPG you will get over time. You still have to use your own judgement though...

@ I remember seeing something like this 'tested' on Mythbusters

... Actually their conclusion was that you could still get a (small) drafting effect at a safe distance. Additionally, if you are very close, you end up braking & accelerating more frequently in order to maintain a static distance & hence start using more fuel.

Stay an absolute minimum of 2 seconds behind ... OK you're not gaining a lot, but you do gain a little (which is better than having to spend $$$ on repairs).

I can't tell the exact benefit, because I have no fuel consumption display, but I experienced that it helps a bit (on a motorcycle it does, at least). Even from the safe 2+ second distance.

It's not worth it to get closer, though. Just like MMUK wrote, it's not "only" dangerous, you'll begin to follow the changes in the truck's speed with braking, so you'll end up losing what you had just gained.

Even safe distance drafting can have this effect under unfavorable conditions, so I don't recommend it except for motorways and other detail-less main roads. Otherwise it's better to be independent :)

I often get behind the truckers on the highway. I obey the "2 second rule" and notice only a couple extra mpgs (on average) over 50 miles of travel.

Thanks everyone. I'll try it next time I'm on my bi-weekly 300-mile round-trip. I figure, if I can do this consistently (and it works), I'll save $48 to $72 a year. (That would just about pay for the exhaust-pipe patch I just had done!)

I am a truck driver and I'm all about saving money but before u get on a truckers *** to try to say 80 bucks in over a years time. Have someone follow u so closly that u can not even see them and know how it feels. If u work in a factory and have ur superviser standing on ur ***. That's how it feels

That's one of the reasons why you should stay at least 2 seconds back (as pretty much everyone has agreed in this thread).

I've got video of a moped rider about a metre or two behind a heavy goods vehicle (travelling at 60mph). Insane.

As a million mile+ driver I recommend staying as far as possible away from large trucks.An "alligator" thrown up can easily take out your windshield.BTW if you can't see his mirrors he can't see you.

The biggest advantage to drafting is seen by being very close to the rear bumper of the vehicle that you're following. As most posters above have already shown, this is incredibly dangerous. If you are within about 4 vehicle lengths you will achieve some fairly significant advantage so staying 3 of your car lengths back will benefit you, but if the truck brakes suddenly you'll be lucky to have enough time to duck in order to avoid the rear bumper as it comes through your windshield.

Another danger to following big rigs closely is your inability to see the road ahead of you, for sighting off ramps, traffic issues, road construction, etc. The danger versus return on this just isn't worth it IMHO.

>...inability to see the road ahead of you, for sighting off ramps, traffic issues, road construction...

Good point there - an important factor in economic driving is to have enough forward view to be able to react to issues well in advance (allowing you to slow down by lifting off the accelerator & hence using the zero-fuel underrun, rather than using the brake, for example).

I agree with the first poster. Myth Busters showed you can save significant gas by tailgating a rig but it's not safe at all. You have to ride their bumper!

Following closer than 2 seconds behind a tractor-trailer will also increase the possibility of rock chips on the windshield and sandblasting the paint on the car's nose. It makes the fuel savings seem minor.

throw a tow hook out on the trailer and drop the car into neutral.

dont bother the dirt the truck kicks up will slow you down airodimamicly

As a previous trucker, I hated it when a car, minivan, etc would do this to me. Can't see them and I would usually slow down enough to make the guy pass me. If I blew a tire it may well end up going through their windshield and killing. NOT a safe driving practice - period.

Thanks, everyone. I had been following about 3 to 4 seconds behind trucks lately, or a car length for every 10 MPH, while making sure that I could see the truck's mirrors. So far, I think I've added 1 to 3 MPG. Not really enough to continue this experiment, but enough to satisfy my curiosity.

The consensus above indicates that drafting on larger vehicles such as big rigs saves a negligible amount of fuel. And aside from the safety issues already mentioned, there is also the long-term damage to your car's finish and windshield from road particles kicked up not only by the 18 wheels but also the turbulence from the undercarriage.

Ask any motorcyclist why he would never draft on a big rig.

>Ask any motorcyclist why he would never draft on a big rig.

I have seen a motorcyclist drafting a HGV by about 6 foot or so a couple of times on my commute... (I wouldn't want to be his life insurer!!)

I always draft big rigs on the beltway. Being in the middle of the lane, I have had zero issues with debris hitting me in my open face helmet. I'm probably 2 bike lengths behind. Just enough that I'm in the low pressure area and I can't feel the wind buffeting my shoulders/arms anymore.

Been a biker since the late 90s and I'll keep doing it.

What happens if there is large road debris (such as a shed tyre)? You have something like 1/10th second to avoid it at that distance & speed which is too fast for human reflexes.

The moment I worry about every little think that might happen on the road is the moment I sell my bike.

Also, you've obviously never been on the Capital beltway or you'd never ask that ;)

99% of my "highway" driving is on the local interstates in the DC area. I have a greater chance of getting killed by a dear (3 close calls to date) than road debris (no incidents). At night, the beltway can be a ghost town. At daylight hours, you can be lucky to get to 65 non-rush and 35 if you're lucky during rush. One little incident can have a ripple effect and it can become a parking lot REALLY quick.

We have a thing here called "rubber neck delays" because of something that happens on one side of the interstate that causes people on the other to slow down to 25-30 so they can look, instead of driving like they should.

I would love to see how Jeremy Clarkson would handle our beltway at rush hour. He would lose his mind, lol.

Back on topic, the reason I draft is you have three choices: Back far off behind the rig so the wind doesn't whip your bike around, pass them if you have that option, or speed up and get in that "pocket". I always choose option 3.

>I would love to see how Jeremy Clarkson would handle our beltway at rush hour. He would lose his mind, lol.

Average driving speed in the centre of London is around 10-12 miles per hour... :-) Clarkson/Hammond/Stig/Capn Slow did a top gear race where they tried different methods of transport through the city. If I recall correctly Hammond won using his bicycle (Clarkson was on a motorboat, Stig was on public transport, James was driving a Merc).

Clarkson also did a London race against a marathon runner, the guy on foot got to the destination first, beating clarkson in his car.

11.8mph average speed according to this article:

https://www.forbes.com/2008/04/21/eur...ongestion.html