General Motors Corp. says its revamped Saturn Vue Green Line mild hybrid-electric vehicle will maintain its 32 mpg (7.3 L/100 km) highway mileage rating, despite changes in federal procedures for ’08 that are knocking down ratings on many vehicles.

The new Vue Green Line, which is expected to hit U.S. showrooms in late November, will base for $24,795, making it the only SUV under $25,000, GM says. (Ward’s classifies the Vue as a cross/utility vehicle.)

The auto maker says it was able to hit the 32-mpg mark even though the Vue went up in weight when it migrated to the new Theta Epsilon platform for ’07 and its 2.4L, 172-hp 4-cyl./automatic transmission hybrid powertrain is a carryover from the old model.

Credited with helping hold ground on highway mileage is a better coefficient of drag, plus modifications to the regenerative braking system and other tweaks.

The 32-mpg rating makes the Vue Green Line the most efficient SUV on the highway, GM says, and it doubles its advantage over the Ford Escape Hybrid to 2 mpg (0.8 km/L). The Escape saw its highway figure decline by 1 mpg (0.4 km/L) because of the new ’08 calculations.

The Vue Green Line’s city mileage rating is negatively affected by the ’08 change, declining to 25 mpg (9.4 L/100 km) from 27 mpg (8.7 L/100 km). The modifications made and the improvement in aerodynamics pay bigger dividends at highway speeds than in city traffic, a GM spokesman says.

The ratings mean the Vue Green Line can travel 585 miles (941 km) on a tank of gasoline, GM says. That’s enough for a drive from Denver to Salt Lake City or Detroit to Philadelphia, and is farther than any competitor’s SUV, the auto maker says.

A base, non-hybrid ’08 Vue starts at $21,395 and is rated at 19/26 mpg (12.4-9.0 L/100 km) city/highway.