Federal highway officials are urging motorists to check their tires after finding that nearly one in 10 passenger vehicles has at least one bald tire.

The U.S. National Highway Traffic Safety Administration (NHTSA) released a study on November 30th which also found that 27 percent of vehicles are driven with one or more highly under-inflated tires.

"It is extremely important to motorists' safety that they ensure their tires have ample tread and are properly inflated," Transportation Secretary Norman Mineta said in a statement. "Motorists who drive on tires that are bald or substantially under-inflated risk injuries or fatalities."

Tire safety has become increasingly important and more publicized since the failure of Firestone tires linked to fatal rollover accidents in Ford Explorers.

NHTSA is launching a tire safety campaign based on the results of its study with the theme, "Tire Safety: Everything Rides On It."

"It is vitally important that motorists monitor tread depth to guard against tire failure and replace unsafe tires," said NHTSA's Administrator, Jeffrey Runge. "Checking tires is a crucial element in regular vehicle maintenance."

According to NHTSA, public service announcements will run on 2,000 radio stations throughout the country, as well as print ads in magazines and newspapers and more than 500,000 flyers given out at tire stores.

NHTSA says that a tire is considered bald if it has 1/16 of an inch or less of tread depth. Tires have built-in treadwear indicators-raised sections spaced in the bottom of the tread groves-that appear accross a tire to inform the motorist that the tire needs to be replaced. Another method for checking tread involves a penny. The driver should place a penny upside down in the tread. If the top of Lincoln's head is visible, the tire needs to be replaced.

According to NHTSA, tires should be inflated in accordance with vehicle maker's recommendations, found in the manual or on a sign in the glove compartment or on the driver's door. The analysis of tire wear was based on information gathered on 6,240 passenger cars during a 14-day period. Information was collected at service stations with the cooperation of drivers who stopped to re-fuel.