(MONEY Magazine) – It seems as if every other TV commercial these days is for a car maker or an insurer touting the safety of air bags. Indeed, 60% of the 1992 models have driver-side air bags as standard equipment, up from only about 1% five years ago. Still, you probably wonder whether air bags work and, if so, which cars have them. There's convincing evidence that air bags do save lives and reduce injuries in head-on collisions, which account for roughly 60% of all auto accidents with serious injuries or fatalities. New studies by the Insurance Institute for Highway Safety and the Highway Loss Data Institute found that, in head-on crashes, there were about 28% fewer driver fatalities and moderate or severe injuries in cars with air bags than in cars without them. Air bags, however, don't work in any other types of crashes, such as sideswiping; the bags pop out only upon front-end impact. The cars providing driver-side bags as standard equipment are mostly medium and large models costing $15,000 or more, as well as all autos made by Alfa Romeo, Audi, BMW, Honda, Isuzu, Lexus, Mercedes, Porsche, Saab and Volvo. Bags are offered only as optional gear (cost: $400 to $500), if at all, on most economy cars. Some makers do include air bags, however, as standard gear on smaller, often sporty models. Among them: Chevrolet Corvette, Dodge Shadow, Nissan 300ZX and Toyota Celica MR2. Hyundai, Saturn and Suzuki, which generally produce small cars costing less than $9,000, do not include air bags in any cars. Minivans with standard air bags are: Chrysler Town & Country, Dodge Caravan and Grand Caravan, Ford Aerostar, Plymouth Grand Voyager and Voyager, and Toyota Previa. If you buy a car with an air bag, shop for an auto insurer who in return will lower your premiums. But don't be fooled. Some insurance companies now boast discounts of 20% or more -- but only on the medical payments or personal-injury portion of the premium. In reality, such a discount works out to a 2% to 5% saving on your total premium.