Drivers could save as much as $2,000 a year on gasoline if they bought the most fuel-efficient vehicle in a segment compared with the one with the worst mileage, a consumer group said Monday.

The owner of a Honda Insight, a two-seat hybrid, would spend $1,850 a year less at the pump than the driver of a two-seat Mercedes-Benz SL600, the Consumer Federation of America said. While the Insight and the SL600 are different vehicles, consumers could save money even when choosing among vehicles that are closer comparisons.

A driver of a midsize sport-utility vehicle would save $1,707 a year by choosing a Toyota Highlander hybrid instead of a Jeep Grand Cherokee, the group said.

Savings ranged from $307 for the consumer who picked the highest-mileage minivan (Honda Odyssey) instead of several others, to $1,995 for the truck driver who bought a Toyota Tundra 4WD instead of a Dodge Ram 8.3L.