Enterprise Rent-A-Car said Tuesday it is more than doubling its gas-electric hybrid fleet with the addition of 5,000 vehicles.

The car rental giant is also designating nearly 80 rental locations across the nation as "hybrid branches,” where customers can reserve hybrids in person, online or by phone.

Hybrids achieve greater fuel economy, use less gasoline and have fewer emissions than traditional vehicles.

Hybrid vehicles include the Toyota Prius, Nissan Altima, Ford Escape and Toyota Camry.

The new hybrids will be available at nearly 80 locations in 24 major markets across the country, including St. Louis.

The other markets are Los Angeles, San Francisco, Sacramento and Fresno, Denver, Orlando, Tampa, Albany, Ithaca, New York City, Rochester, Eugene, Ore., Portland, Ore., Austin, Dallas, Houston, Atlanta, Boston, Detroit, Minneapolis, Philadelphia, Seattle and Washington, D.C.

Enterprise, the largest privately held company in St. Louis with more than $13.1 billion in 2007 sales, employs more than 4,000 people in St. Louis area and more than 75,000 employees worldwide, including the Enterprise, Alamo and National brands.