Stability Control
Studies suggest that passenger cars with electronic stability control (ESC) are engaged in 35 percent fewer single-vehicle crashes than the same models without ESC. By 2003, ESC was on about 7.3 percent of light vehicles (cars and trucks). Today, about 40 percent of vehicles already have ESC. The NHTSA calculates that mass production of basic ESC could put the cost at about $100 per vehicle.

ESC has been around a while: It’s an outgrowth of antilock braking, introduced in the 1980s, whose primary benefit is the avoidance of skids in sudden stops. ESC also builds on the success of traction control, which uses electronics to keep drivers literally from spinning their wheels in conditions of slick pavement or overaggressive acceleration. At its most basic, ESC combines the control of braking with that of throttle to prevent drivers from spinning out on curves or rolling over in sudden maneuvers.

Like computers, electronic systems in automobiles get increasingly powerful each year. ESC is about to become even smarter: GM’s Stabilitrak, for instance, enters its third generation next model year and will incorporate steering input in addition to the control of the brakes and throttle.

Collision Mitigation
Also known as anticipatory braking, collision mitigation represents a step beyond smart cruise control and involves the use of radar to anticipate a crash and charge the brakes for better stopping. These systems are rapidly evolving. The latest DaimlerChrysler system combines two radars, one with a narrow angle aimed at distant objects and one with a wide angle to measure lateral distance at closer range. The combination gives the car’s brains a near 3-D sense of objects around it.

Similarly, Lexus combines a distant radar that focuses on hard objects, such as other cars, with a short-range beam tuned for softer ones — people or animals. A similar bmw system is called Dynamic Brake Control. Volvo's City Safety, a still-experimental system, adds computerized steering control in addition to the more common braking input. City Safety has been demonstrated on concept vehicles, but it is likely to appear on production models soon. A system called V2V (Vehicle to Vehicle) now under development at General Motors would forgo radar and instead locate other cars on the road using Wi-Fi and GPS technology.

Blind Spot / Lane-Departure Warning
Several new high-tech systems aim to protect against collisions to the side of the vehicle. Volvo’s new S80 sedan offers a system that warns of other vehicles in the driver’s blind spot. Shown several years ago in the company’s Safety Concept Car, the Volvo BLIS (Blind Spot Information System) illuminates a red warning in the side mirror when its sensors detect a passing car.

A related safety feature is lane-departure warning. If a driver drifts out of his or her lane, a warning buzzer or light goes off. Lexus calls its system Lane-Keeping Assist, available on the LS 460 and other models. Lane-Keeping Assist uses cameras that capture an image of the surrounding highway and dotted roadway lines on both sides of the car. The system sends an alarm and intervenes with steering to keep a wandering driver in line.

Infiniti introduced its version, called the Lane Departure Warning System, on the FX SUV and offers it on the M sedan as well. A small camera reads the dotted lines in the road and combines the information from speed sensors to calculate motion and course. Flipping the turn signal deactivates the system, and there is manual override to turn it off completely. Audi’s Side Assist uses two radars and a rear camera tracking road lines. These work up to a distance of 16.5 feet and activate yellow lights in the side mirror if another car passes into the danger zone (the blind spot). The system has no auditory warning and can be turned off entirely.

Bear in mind that these systems 100 percent effective yet: Because most rely on visual cues taken from cameras, they can get confused when the road lacks well-painted lines or mud obscures them.