Fuel cells hold the potential to replace internal combustion engines. Within the decade, steer-by-wire and brake-by-wire are expected to supplant the mechanical components that have been guiding and stopping motorists for generations. Satellite radio, downloaded MP3 audio files and the Internet will give motorists unprecedented entertainment options.

The future holds a truly impressive array of technology for the automotive industry. But it's worth noting that despite these advances, the basic method of passenger protection, arguably the auto industry's most important obligation, stands virtually unchanged.

Seat belts have been on U.S. vehicles for 37 years, and air bags have been phased in over the past eight. Both will continue to improve in the coming years, but no one foresees a technology to replace air bags and seat belts as the best way to manage crash forces within the cabin.

Despite Hollywood's keen foresight, cars will not fill up with foam the way they did in the futuristic movie, "Demolition Man."

The big development to come in occupant restraints already has faded from the American psyche. A few years ago, the rage was "smart" air bags that deploy with less force or not at all depending on occupant position and other factors. How else can the industry respond to the negligent parent who allows his 2-year-old son to bounce around on the front seat unbelted, without a car seat?

Many drivers probably think air bags on their new vehicles already are "smart," but they would be surprised to learn that the National Highway Traffic Safety Admin. has yet to define the attributes of such a restraint. That definition is expected in March. It will be another five years before smart air bags are required on all new vehicles.

In the future, air bags will be more closely integrated with seat belts, they will be adaptive and there will be more of them. Occupants could find air bags at their knees, feet, hips, head and even wrapped around their seat belts.

Sweden's Autoliv Inc. recently opened a new plant in Tilbury, Ont., to produce one-piece woven inflatable curtains for a number of high-volume North American vehicles to improve head protection.

Autoliv introduced the product last year on Volvo, Mercedes-Benz, Toyota and Audi vehicles and in 1998 produced 200,000 inflatable curtains at its plant in Manchester, U.K. With contracts now in-hand, Tilbury will produce 2 million inflatable curtains in 2000 and 3.5 million in 2001.

Ultimately, the next breakthrough in safety lies in preventing accidents from occurring at all.

Radar can detect stationary and moving objects and react even before a collision occurs by tightening the seat belts and firing the air bags early, with an eye on significantly reducing or preventing injury.

Radar is the controlling factor behind adaptive cruise control, which allows a vehicle to automatically accelerate, decelerate or even brake, depending on traffic conditions.

A vehicle can be wrapped with more sensors or CMOS-based digital cameras to monitor moving vehicles behind, beside, or in front - sort of an "electronic cocoon," as one expert calls it. Get too close and the vehicle could automatically decelerate or accelerate to avoid, or at least lessen, impact.

Such a system could be on U.S. vehicles within 10 years, says Kenneth Francis, North American director of safety and chassis electronics for Siemens Automotive.

Within five years digital cameras could monitor eye blink rates and even alert a driver who is dozing - another form of collision avoidance.

Despite the gee-whiz gadgetry, the first safety innovation - the seat belt - remains a remarkable achievement. Between 1975 and 1998, seat belts saved an estimated 112,000 lives. Still, only 68% of Americans wear them.

Brian Przysiecki is sure they saved his life in 1998 when someone in a pickup turned in front of him on a two-lane highway in rural Shiawassee County, MI. Mr. Przysiecki was driving a 1984 Chevrolet pickup and was towing an empty trailer.

He could not avoid a collision, but the former demolition derby driver managed to steer so the passenger side took most of the force. The trailer jackknifed, dislodged and took off down the road.

His pickup was a mangled mess, but he survived because his 7-year-old son Devon had told him 20 minutes earlier to buckle up. Devon was belted in the middle seat, right next to his father. They both walked away with minor injuries, although Mr. Przysiecki continues to have back pain.

He can only speculate as to the outcome if his truck had been equipped with air bags. As for seat belts, he didn't think much of them before, but now he won't drive without them.