YOUR car has hit a patch of ''black'' ice, sending it swirling like a whirling dervish until it plows backend-first into a snow pile. If only you'd seen that slick spot. But you're okay, and so is the car.
Thanks to some breakthrough technology, such a stomach-wrenching experience may become rarer. The new system not only detects dangerous road conditions, but it responds so quickly drivers may never know they've been in trouble. And that could have a profound impact on highway safety, experts say.
The new technology -- involving a silicon chip, appropriately named ''ESP,'' for Electronic Stability Program -- debuts next fall on the Mercedes-Benz S-Class sedans. Similar hardware, generically known as Stability Management Control, is under development at BMW, Ford Corporation, and a variety of other suppliers and automakers.
To pull off its fancy trick, ESP requires a basic Antilock Brake System, or ABS. Sensors on each wheel detect brake lock-up, a sign the car is beginning to lose its grip on the road. When that happens, an on-board microprocessor automatically pumps the brakes, much like a skilled driver does, until the tires regain traction. A more advanced system, known as Traction Control, works when a car skids while accelerating, either by pumping the brakes, or easing back on the throttle to reduce power, or both.
Stability Management Control adds two additional sensors. One, hidden within the steering wheel housing, measures precisely how much the driver wants to turn and how fast. A yaw sensor is also mounted on the chassis, which measures how much the car is actually turning. The sensors compare the two signals and determine whether the car is in a skid. Within as little as 50 milliseconds, the computer responds, like Traction Control, with the brakes and throttle.
At freeway speeds, Stability Management will begin to respond before the car has traveled six feet. It takes an alert, well-trained driver at least six times as long to realize the car is skidding -- and even longer to take corrective action.
''This invisible hand keeps the vehicle where the driver wants it to go,'' says Johannes Graber, program manager for ITT Automotive, which is developing a version of the technology it calls Automotive Stability Management System. (The other major supplier is Germany's Robert Bosch, which supplies the hardware for Mercedes' ESP.)
Studies suggest as many as half of all single-car accidents are caused by improper steering maneuvers. That is why ''active safety has become a high priority for us,'' says Herman Gaus, Mercedes-Benz director of passenger-car development.
Mercedes may be first to market, but it won't be alone for long. BMW is barely a year away with its own Stability Management Control. And Ford is expected to introduce a version by late 1997.
''This could become as common as antilock brakes,'' suggests Klaus Lederer, who runs ITT Automotive's European brake operations. Cost will be a big obstacle at first. Depending on the model, ESP will cost Mercedes customers as much as $2,000.
Stability Management is only the next step in ''smart car'' technology. During a recent test drive at its Arctic research facility in Arvidsjaur, Sweden, ITT Automotive engineers unveiled a new ''brake-by-wire'' system.
Normally, when you step on the brake pedal, hydraulic fluid is forced to each of the vehicle's wheels. With brake-by-wire, the brake pedal is little more than an electrical switch, and when pressed its signal is transmitted to the motorized brakes on each wheel. By the time this technology goes into mass production, the wire itself will likely be replaced by fiber-optic cable.
Other auto technology ahead:
* Ford is developing a concept called Interactive Vehicle Dynamics. With IVD technology, the car's microprocessor will not only control braking but also the suspension system. When a driver goes into a hard turn the technology will firm up the shock absorbers on the outer wheels, improving a cars cornering capabilities.
* Another technological step will link the brakes to a radar transceiver mounted near the front bumper. The transceiver will sweep the roadway with an invisible beam of radar. Greyhound already uses this technology to warn bus drivers of a potential collision.