Sure, a six-foot protrusion sticking off the rear end of any vehicle is kinda funny looking. Unless we're talking about a Porsche 917/30 or a Plymouth Superbird. Those cars have some very fine rear extensions. Okay, fine – a six-foot protrusion looks a little bit weird when growing out of a semi-truck's rear. Happy?

But a boat-tailed tractor trailer might be just what we need. Why? Because when fitted with such a piece of aerodynamic kit, total fuel-consumption reportedly drops by 7.5%. The tests in question were conducted by the Dutch PART (Platform for Aerodynamic Road Transport) public-private partnership platform on public roads. One truck without any aero-aid was driven around for a year, as was another truck with the boat-tail.

Not only did the boat-tailed machine get a 7.5% fuel economy bump, but at the same time, emissions were slashed by about the same margin. Even though these numbers are indeed promising, PART wants to figure out a way to reduce semi truck fuel consumption and emissions by 20%.

[Source: Science Daily]