New Fuel-Economy Rules For Trucks

New fuel-economy standards to be announced this week could mean major changes for truck mileage standards. For the first time, these new rules will include previously exempt heavy-duty models, such as the Hummer H2.

The National Highway Traffic Safety Administration will make these new rules public some time this week.

The new rules could potentially put pressure on automakers to improve the mileage of their heaviest vehicles, often referred to as the "three-quarter-ton" or "one-ton" trucks. The new rules will apply only to trucks.

Heavy-duty pickups would continue to be exempt because they are considered work-trucks rather than personal vehicles. According to the Union of Concerned Scientists, this could create a huge loophole, since approximately 80% of heavy-duty trucks sold are pickups.

The basis of the new system is an index number that will be calculated using wheelbase and track.

The NHTSA regulations determine if an automaker should be fined for selling too many low-mileage trucks or not enough high-mileage trucks.