Automakers have developed some spiffy new technologies for their newest cars that promote safe driving and help to prevent accidents.

Caution: These state-of-the-art devices can help you avoid accidents, but they aren’t a substitute for good driving.

Here are several new accident-avoidance gadgets and systems that are standard or optional in many cars (at this time, these technologies are not sold separately)…

LIMITS FOR TEEN DRIVING

MyKey, developed by Ford, allows concerned parents to limit the speed of the vehicle that their teen is driving to 80 miles per hour (mph). Although the speed limit throughout much of the US is 70 mph, Ford decided to set the limit at 80 mph in case a driver needs to accelerate to avoid a crash. Nothing limits the MyKey system to teen drivers — it can be used by any driver who does not want to top 80 mph. MyKey can be set up to sound a chime if the driver exceeds 45, 55 or 65 mph.

Bonus: Driving at lower speeds can help fuel economy.

The MyKey system also enables parents to control other in-car functions, including the maximum volume of the sound system, and the car can be programmed to emit warning chimes if occupants aren’t wearing their seat belts. An owner-programmable ignition key is the heart of the system.

Available in: 2010 Focus compact and Escape SUV. Ford plans to offer MyKey on many other models in the future.

Around View Monitor

Infiniti (Nissan’s luxury car division) has developed an unusual “panorama view” backup camera that now is available on certain models and may be available on others in the future. It gives the driver a bird’s-eye view (as seen from above) of the perimeter around the car — not just what’s behind the rear bumper. Mini-cameras with wide-angle lenses are built into the sides, front and rear of the car.

Around View works with the vehicle in drive and reverse (at low speeds up to about 5 mph) and can be helpful when maneuvering in confined spaces.

Available in: Infiniti EX and FX SUVs.

Caveat: The image on the LCD monitor is slightly distorted, which can make it difficult to accurately judge exactly how much room you’ve got to work with. Always check twice before backing up — and proceed slowly.

Automatic Braking/”Active” Collision Avoidance

Pioneered by Mercedes-Benz, this technology uses radar to detect vehicles and slow-moving objects in the vehicle’s path (or excessive closing speed between your vehicle and another car). The system can apply the brakes automatically without the driver’s input. In Mercedes-Benz vehicles, such as the 2010 E-Class and S-Class sedans, the system works with the cruise control to decelerate and accelerate the vehicle with the ebb and flow of traffic. It can bring the car to a complete stop and resume the vehicle’s speed without the driver touching the brake or gas pedal.

The system is designed both as an emergency safety measure — applying the brakes in the event that the driver fails to notice a dangerous situation, such as suddenly stopped traffic ahead — and as a convenience, because it allows “set and forget” cruise control operation.

Available in: Mercedes-Benz 2010 E- and S-Class sedans, E-Class coupes and Volvo S80 sedan.

Caveat: This technology may cause the vehicle to brake even when you don’t want it to. The system can be turned off by the driver.

Lane-Departure Warning

Infiniti pioneered this system, which emits a warning beep whenever the vehicle begins to stray over a double yellow line (and potentially into oncoming traffic) or other painted lines. The system can be turned off by the driver in situations where it would give false alarms, such as when driving across parking lots with painted lines.

Available in: Infiniti EX and FX SUVs and M sedans.

Driver Alertness Monitor

Developed by Mercedes-Benz, this system detects when a driver is falling asleep at the wheel. When sensors note decreased or inappropriate steering, the system emits an audible warning signal to try to wake up the driver. The system can be turned off by the driver.

Available in: Mercedes-Benz 2010 E- and S-Class, except the S400 Hybrid.

Caveat: It’s possible that the sudden audible warning could startle an already half-asleep driver and cause him/her to jerk the wheel or jam on the brakes. Because the system is new, there is no data yet on its effectiveness.

Important: Always get plenty of rest before you drive. Take a leg-stretch/bathroom break every three to four hours — and make an overnight stop after spending eight to 10 hours behind the wheel.