The tapering tail is no secret among scientists for improving stability and fuel efficiency. Many high-mileage concept cars feature just such a design to smooth the aerodynamics of the vehicle. Now imagine applying the same concept to container trucks that log more miles in a year than most of us travel in five.
A Dutch public-private enterprise did just that, adding a 6 foot long tail to the end of a tractor trailer truck. The results from two years of testing were a 7.5% increase in fuel efficiency, and thus a similar decrease in emissions.
While it may not look like much, in the world of competitive trucking every little bit counts. A 7.5% increase may only turn out to be a 1 MPG difference, but over the course of 100,000 miles…that adds up. The tail is designed to fold out of the way during loading and unloading, though it looks like it could still stand some improvement in that area. The developer of this tail is Platform for Aerodynamic Road Transport (PART), who has developed other ideas for improving auto aerodynamics as well (see below).
The tests were first conducted on computers, and then in wind tunnels before tackling the open road. The test truck ran a year without the tail across the Netherlands, and then a year with the tail to come up with the results, which seems like some pretty solid data if you ask me. The only problem with these kinds of trailers here in the states is a length restriction. The tail adds six feet to the end of a trailer, and certain states (like good ol’ Connecticut) only allow 48′ trailers with a 43′ foot kingpin-to-rear-axle measurement. Most of the country allows for longer 53′ trailers, but ultimately it may come down to fuel savings versus cargo capacity.
Or they could just build tapered trailers and make it easier on everybody. This simple solution could be implemented almost overnight (if we got the government and private businesses to cooperate for once) and save hundreds of millions of dollars in fuel costs and annual emissions. And if you combine this technology with simple side skirts, the fuel savings could be over 20%! The sideskirts are also part of the Dutch PART initiative.