The Cadillac's front seat belts didn't look any different than ones in other vehicles, nor did they force me to buckle up in an unusual fashion. But Mike Chia, a test engineer from Delphi, warned me that they were “pre-tensioning seat belts,” which meant that if I'd never been strapped into them before — and I hadn't — it might feel a little strange. Especially since we'd be simulating a frontal collision.
Strangely, the hair on the back of my neck stood up at that point. Go figure.
This was all part of a ride-and-drive event at the Robert F. Kennedy Memorial stadium in Washington D.C., sponsored by the Motor & Equipment Manufacturers Assn. (MEMA) and its subsidiary, the Heavy Duty Manufacturers Association (HDMA). Test drivers took participants for spins in tractor-trailers, concrete mixers, cars and light trucks fitted with a variety of safety technologies to show how these devices work in the real world.
Chia explained that Delphi's pre-tensioning seat belts use special motors connected to a sensor array, enabling them to cinch tightly around someone in the front seat way faster than standard mechanical spring-based belts. But they also operate very differently. After I buckled up and Chia started the engine, the seat belt tightened slowly around me, “gauging” my body's dimensions and encouraging me to reposition the lap belt portion if it tightened around my stomach and not my hips.
While the “gauging” process felt weird, it only lasted a few seconds. The fun began when Chia shifted into drive and started down the test track, heading for the collision target: a foam pad attached to a long steel rod attached to the back of a modified minivan.
Sensors in the Cadillac's grill registered the target and, as Chia gunned the motor to close in on it, the seat belt automatically tightened around me in preparation for a crash. Just how tight depended on the speed of our Caddy relative to the target.
Nice safety feature, these belts — which, by the way, are currently available. Yet it's not all about crash safety. I later talked to William Shogren, Delphi's chief engineer for advanced vehicle systems, who told me that motorized seat belts connected to sensors could improve the driving experience in a much broader fashion.
“Many drivers complain that it's hard to make seat belts comfortable,” he said. “When they are motorized like this, you can put a lot more slack into the belt, so it hangs far more loosely on the driver, because it will tighten faster in a crash situation and to the appropriate pressure as dictated by the sensor readings.”
There's also a fatigue-detection angle, he noted. If sensors are added to the seat belt itself, it can detect when a person's body angle begins to change-such as slumping forward or to the side when falling asleep The sensor readings activate the belt, jostling the driver awake, Shogren said.
Delphi also equipped its Cadillac with: “active braking” systems. With cruise control on, the same crash sensors used by the smart seat belt would automatically activate the brakes to maintain a safe following distance from the vehicle in front of it, fully deploying them if that vehicle were to come to a complete stop.
In fact, while in cruise control, Chia could not fully crash our Caddy into the foam target because the brakes kept deploying to reduce — and in some cases totally eliminate — the impact.
Great stuff, and it can only serve to improve the lives of commercial drivers of all vehicles — light to heavy — if we start using it.