WASHINGTON — Drivers protected by air bags are significantly less vulnerable to head and chest injury in accidents, government tests results released Friday indicate.

The most recent test results released by the National Highway Traffic Safety Administration indicated that a front-seat passenger in the Chrysler LeBaron two-door convertible is nearly seven times as likely to sustain head injury as the driver.

In the Chrysler Imperial, a four-door sedan, the passenger is four times as vulnerable as the driver.

Both cars have air bags on the driver’s side.

The agency tested 34 vehicles ranging from subcompacts to luxury sedans and light trucks, releasing it final round of crash test results for 1990 automobiles.

Chrysler spokesman Steve Harris said it was difficult to draw conclusions from the tests because they were based on crashes under conditions that exceed government safety standards but he said air bags have a major impact on safety and are needed for passengers as well as drivers.

“Everybody (in the auto industry) has indicated that’s the direction they’re going,” he said.

The government tested the vehicles by driving them head-on into a fixed barrier, creating the same conditions as a frontal collision between two identical vehicles driving at 35 miles per hour.

The conditions also are equivalent to a car moving at 70 mph striking an identical parked car.

Test results apply only to occupants using seat belts and, in certain cars, air bags. Tests are conducted using dummies that represent an average-size adult male.