MythBusters: Does Drafting Semis Improve Fuel Economy?

[omgwtfbyobbq]

Yeah, but that can happen any time. It's not specific to drafting, or valid when talking about it. I can take my eyes off the road for a second and hit a semi, car, dog, child, inanimate object, black hole, etc... You should never take your eyes off the road, ever.

[omgwtfbyobbq]

No. Then time stops until after she walks by. When it resumes, you can explain to the officer that you couldn't have been the one to run down that ten year old on their bike, since the hot lady was there and clearly, time had stopped. Btw, there are plenty of kids where I live if you feel inclined to test this, unfortunately you have to bring the hot chick.

[omgwtfbyobbq]

*sigh*

[BumblingB]

About 6 years ago Car & Driver did one of their crazy challenges among the staff. It was to see who could get the best mileage from point A to point B (Chicago to somewhere if I recall). It was for who could get there the quickest AND get the best mileage. They ended up getting a Honda Insight and a Ford Excursion. They opened the rear doors/hatch of the Excursion and built some contraption out of plywood to go in it as well. Then they drove the Insight on the route inches behind the Excursion. I think the end result was something like 120mpg. Drafting works for better MPG, but something can be said for safety and the damage it does cause to your car though.

[Silveredwings]

Originally Posted by DRW

One of the previews showed them drafting within a foot of the trucks rear bumper. Just a little dangerous, ya think?

How about testing the myth that the trucks FE goes down when they're being drafted?

Some amount of the aerodynamic drag on a tractor-trailer results from the turbulence created behind its huge flat rear end. We already know about improvements from adding a boattail, so why wouldn't a trailing vehicle that broke that turbulence up a little actually help the truck's FE, even if only slightly?

And yes it does somewhat resemble a death-wish.

[slurp812]

Originally Posted by omgwtfbyobbq

Yeah, but that can happen any time. It's not specific to drafting, or valid when talking about it. I can take my eyes off the road for a second and hit a semi, car, dog, child, inanimate object, black hole, etc... You should never take your eyes off the road, ever.

Yup, and in crazy traffic this weekend, I drove over a frickin tailpipe! So did most of the cars in front of, and behind me. Single lane bumper to bumper rush hour traffic in a construction zone. what fun!

[Snax]

There seems to be a misconception, perhaps from NASCAR announcers, that an effective draft needs to be done at arms length from the next vehicle. Considering they are referring to cars that are supposed to be slippery, that would make sense. Conversely, a big box trailer aint slippery, and multiple trailers actually accelerate the air the direction of travel, creating a current.

You can generalize drafting as dangerous if you want to, but consider that the benefits of it can be exploited as far back as 200 feet from a triple trailer doing 60mph. Even cutting that distance in half is hardly walking the tightrope of safety.

[Hockey4mnhs]

3 triple trailer damn i want to find one of those!

[Snax]

I don't think they are legal in every state in the US, so they aren't very common. UPS and some of the regional chain stores use them most often.

[Peakster]

I was drafting a double-trailer semi on the freeway recently at ~55mph (about 5-6 Geo-lengths away) and was seeing MPG numbers well into the 70s.