While the railroads may have built America, there's no question that today, the trucking industry keeps it rolling. The creation and expansion of the Interstate Highway System has connected all but the smallest American cities to this massive freight transportation network, and other than a few locally-produced niche products, nearly every consumer product in America has found its way into the trailer of a big rig at one point or another.

However, this massive industry has one critical flaw—complete dependence on petroleum. The ecological effects of diesel exhaust pollution, along with the economic impacts of a highly volatile oil market, could have disastrous results for the shipping industry and consumers alike.

Fortunately, a new study by the Union of Concerned Scientists reveals that several key technical upgrades already on the market could massively reduce the reliance of the nations heavy truck fleet on oil, slow the pace of global warming, and improve environmental conditions nationwide.

By far the most impressive gains can be gleaned through improving the aerodynamics of the truck cab. High roof fairings, which sit on top of the cab, form a minimally disruptive slope to the top of a standard 53-foot trailer, dramatically improving airflow around the vehicle. Fairings can also be added around fuel tanks and exhaust stacks. While some of these retrofits can be added to older, boxier-style cabs, the most impressive gains come on newer cabs that have been designed for aerodynamics from the ground up, and can improve efficiency by up to 15%, saving 2,500 extra gallons of fuel per truck.

The truck trailer itself also offers tremendous room for improvement. While the traditionally-shaped trailers stack well, their flat sides and sharp edges create massive amounts of drag; improving this airflow with skirts along the side of the trailer between the wheels, and with specially-shaped additions to the front and rear, can reduce this drag by 20%, leading to a 10% improvement in fuel economy.

Tires and wheels can also put significant dents in heavy truck fuel dependence. Higher-efficiency tires offer improvements of 3% over average models, while using single tires instead of side-by-side tire designs, lowers both rolling resistance and aerodynamic drag. Finally, lighter aluminum wheels can reduce the energy needed to get the truck up to speed, and taken with these other wheel-and-tire based improvements can improve fuel use by roughly 5%.

Taken singly, none of these improvements makes an overwhelming difference in fuel efficiency.  As a complete retrofit across large portions of the American truck fleet, however, gains could be massive. UCS estimates that for most long-haul truckers, payback times on the new investments could be as short as two years. Across the average lifespan of a big-rig, this could yield savings of more than $30,000, 17,000 gallons of fuel, and 220 tons of global warming pollution per truck, not to mention significant cuts in volatile gas and smog-forming emissions.

Photo by Flickr user tomsaint11