International Truck and Engine Corp. officials said they have come up with a prototype of an aerodynamic system that reduces air drag by 14 percent.

According to a company press release, the key features are a cowling that closes the gap between the tractor and trailer, skirts on the sides of the trailer, a tapered trailer rear, and a slightly lowered trailer top in the front.

The prototype was developed for Wal-Mart, which has announced it wants to dramatically increase the fuel efficiency of its fleet.