Heavy-duty trucks spend more time on the road than passenger vehicles, so improving their efficiency can have a major effect on emissions--and their owners' bottom lines.

That's why Walmart is getting into the truck-design business with the WAVE--Walmart Advanced Vehicle Experience--concept.

With its aerodynamic cab, the WAVE certainly doesn't look like any other large truck currently on U.S. roads.

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The design was achieved in part by placing the driver in the center of the cab. The steering wheel is flanked by LCD screens--in place of conventional gauges--and there is a sleeping compartment directly behind the driver's pod.

The WAVE features a range-extended electric powertrain, consisting of a Capstone micro-turbine and an electric motor.

Walmart WAVE concept truck.

entire truck is made of carbon fiber--including the trailer

trailer is made from carbon fiber.

Walmart says this is the first example of a carbon-fiber trailer ever produced, and that its 53-foot side panels are the first single pieces of carbon fiber that large that have ever been manufactured.

Like the tractor, the trailer was also designed for optimum aerodynamic efficiency. It features a convex nose, which not only reduces aerodynamic drag but has the added of benefit of increasing cargo space in the trailer.

Walmart says the carbon-fiber trailer is around 4,000 pounds lighter than a conventional one, allowing a truck to carry more freight without the need for increased power or fuel consumption.

The retail giant did not reveal any plans to produce the WAVE, and in fact it would be highly unlikely to get into the truck business.

But it's far from the only company encouraging ways to make big trucks more efficient.

The streamlined AirFlow BulletTruck achieved 13.4 mpg on a recent cross-country trip, while Peterbilt and Cummins' "SuperTruck" achieved 9.9 mpg last year.

Those numbers may not sound impressive, but they're significant improvements for vehicles that typically get 5 or 6 mpg.

They'll also be necessary in the near future: President Barack Obama has directed the Environmental Protection Agency (EPA) to draft a new set of fuel-economy rules for medium and heavy-duty trucks.

These standards will take effect in 2019 and run through 2025, picking up where the current standards--which date to 2011--leave off.

Updated: A previous version of this article stated that the entire truck was made from carbon fiber. The trailer is entirely carbon fiber, but the tractor is not.

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