"Car buyers tend to automatically focus on the affordability of monthly payments, but that's only one part of the financing equation," said Brian Reed, vice president with Capital One Auto Finance. "You also need to look at your APR, the total amount financed and the length of your loan."

Experts say consumers can take a number of steps to help guard against becoming upside down on their next car loan.

• Comparison shop for loans. Explore rates at your local bank, credit union or online at sites like www.capitaloneautofinance.com. Capital One offers consumers a no-hassle auto lending program with nationally competitive rates. Secure your own no-obligation loan before you go to buy, to increase your leverage.

• Buy a car that retains value. Check out Web sites to see which vehicle makes and models best hold their value. By choosing a lower-depreciating vehicle, you'll be protecting your equity when you go to sell.

• Match length of loan to length of ownership. Select your loan term based on how long you plan to own the vehicle-and stick to that term.