Coming to a highway near you? Tapered semi-trailers
Semi-trucks are constantly cruising the highways of America, delivering everything from organic basil to La-Z-Boy recliners. All the miles that truckers put on these modern beasts of burden use a lot of gasoline, but the European public-private consortium behind Platform for Aerodynamic Road Transport could be here with a fairly simple and elegant solution: tapered rear ends.
PART claims that the six-foot device that hangs off the rear end of the trailer can improve fuel efficiency up to 7.5 percent. That's not a terrible increase for the Prius. On ultra-low MPG vehicles like these, it's a huge deal. PART has been testing these tails for two years, and also has a lot of other aerodynamic ideas for large trucks: side panels, aero mirrors, and even aerodynamic mud flaps. Put everything together on one truck, PART says, and you'll see fuel economy improvements of more than 20 percent. Almost makes us want to become truckers.
[Source: PART via Gas 2.0]

Reader Comments (Page 1 of 1)
GoodCheer 11:19AM (11/13/2009)
"All the miles (...) use a lot of gasoline"
Em... no. The vast majority of those miles are powered by diesel fuel.
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JustZisGuy 3:08PM (11/13/2009)
Actually, since the article is about "semi-trucks", I would venture a guess that ALL of that distance is powered by diesel.
But hey, diesel, gasoline, who would be aware of the difference unless they were reading something like autobloggreen where there are constantly posts about diesel-powered cars...
(It also drives me batty when pilots of turboprops or jets talk about "gas". Believe me, it matters. Going the other way, if you manage to put jet fuel in a piston powered airplane, people will likely die as a result.).
80N541 12:00PM (11/13/2009)
it will never appear in europe. Here, the length of truck is limited, this is why the driver's cabin is on top of the engine (to have more charging room in the trailer)
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aimless 7:04PM (11/13/2009)
License plate OG-75-TL.
It's a trailer from the Netherlands. So it can be done, if only in an experimental vehicle.
Tapering the back without offending the vehicle code will limit the useful size of the trailer a bit. Every operator will have to do the maths. What is more cost effective, saving fuel or taking that last pallet?
European semi trailers can be up to 54 feet overall length and 40-44 tons gross weight.
Some countries allow permits for doubles up to 82 feet and 60 tons.
Gordio 12:24PM (11/13/2009)
Hey no fair. I thought of this design next time i better rush to patent office quicker...
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Ghen 3:07PM (11/13/2009)
Of course you did, random internet guy.
meme 1:30PM (11/13/2009)
I don't know why you'd want to extend it with *useless space*. If you're going to add an aero taper, why not make it room that can be used? Or if you don't want to increase the length, why not taper the existing body?
The reason it's not a huge help is partly because since they haul such heavy payloads, despite their big aero profile, most of their losses are rolling losses. But hey, 7.5% is 7.5%. :) For a semi driver, that's many thousands of dollars back in your pocket per year.
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CH 10:11AM (11/16/2009)
The problem I see with using it as additional cargo space is that the aperture is smaller then the rest of the truck, thus limiting the size (height and width) of the freight you want to load. However if you’re going to put something this far out, why not go completely aerodynamic:
http://green.autoblog.com/2007/01/01/radical-truck-designs-by-luigi-colani/
http://www.bangertinternational.de/colani/images/preview/Colani_20.jpg
http://www.news.ch/img/wallpapers/colani-space-truck-1024x768.jpg
dwarg 1:24PM (11/13/2009)
There must be some legal hurdles in having something sticking out that far behind the back wheels. As the truck pivots on those wheels everything behind them swings outward into the next lane of traffic.
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T at Clarkson 1:40PM (11/13/2009)
From 2005:
http://www.clarkson.edu/news/view.php?id=1354
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Ernie 1:46PM (11/13/2009)
Or.... you could ship by train and get a 220% improvement in fuel efficiency.
Someone did the math here: http://gadgetopia.com/post/5294
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paulwesterberg 2:40PM (11/13/2009)
And all modern trains are either electric or hybrid.
Unknown 4:29PM (11/13/2009)
Or.... you could ship by train and get a 220% improvement in fuel efficiency
If you dont mind a 2 to 3 week wait to get it across country
Ernie 5:07PM (11/13/2009)
Unknown: and your experience with this is...?
Unknown 10:25AM (11/16/2009)
Unknown: and your experience with this is...?
Shipper .... and yours?
Ernie 12:06PM (11/16/2009)
I have no such experience. But it *is* a good idea to qualify your claims, as I did.
While some shippers have no trouble with the extra time (non-perishable items, for example), it probably does demonstrate some inefficiencies in the shipping process. Just for comparison, how long does it take to ship that same distance by truck?
RPM 11:19PM (11/14/2009)
i'm wondering how you back into existing unloading bays with that big a$$ thing hanging on the back end...even if it swung to the side out of the way..it would be in the way of the bay next to you. And how can you say this thing looks elegant?? i guess its all in the eye of the beholder.
as far as trains..try 3 to 4 days to cross..much more efficient than truck and you get a lot of these big trucks off the roads - one train can hold 200-300 trailers..thats a lot of trucks not clogging up the highways tearing up the roads...as far as the wait ..I thought most of you environmental nuts liked riding bikes and taking public transit to get to places...they also take a lot longer to get from point A to point B than a car...
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PBandJay 3:43PM (11/17/2009)
These things are pretty cool and I know there is an American company making these http://atdynamics.com/
@RPM - I have seen several of these that fold up nicely and even allow for the swing doors to latch to the sides of the truck like normal.
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