(MONEY Magazine) – Last month, when we rated 90 cars, trucks and vans for safety, we told you that side air bags provide valuable protection in a crash. Now the National Highway Traffic Safety Administration (NHTSA) is warning that side air bags, although an important safety feature for adults, could injure or kill children who are leaning toward a bag when it opens. As a result, NHTSA has asked automakers to ship cars to dealers with side air bags in the rear turned off.

This action doesn't change our ratings of the models with side air bags. NHTSA--which performs crash tests using dummies that approximate a five-foot-nine, 170-pound adult--still contends that side air bags improve your chances of surviving a crash.

However, if your vehicle has side air bags in the front, you should follow the standard safety procedure of seating all children under 12 in the back. If your car is one of the rare models with rear side air bags and children ride with you regularly, have the dealer disable the rear bags.

For 2000, rear side air bags are available from Audi (standard on the A8, optional on the A6), BMW (optional on all four-door models), Cadillac (optional on the DeVille) and Mercedes (standard on the S and E class sedans and the M class SUV). BMW already ships cars to dealers with rear side bags disabled. Both Mercedes and Cadillac say they don't plan to deactivate rear bags at the factory because their tests have found them safe for children. Audi is still considering a response.

--JERRY EDGERTON