Front air bags are now standard on all new vehicles, and can actually be found on many used cars. Crash sensors connected to an onboard computer detect a frontal collision and trigger the bags. The bags inflate in a few milliseconds. Air bag technology has saved thousands of lives each year. It is important, though, to note that they can do damage if not used properly; children under twelve should never ride in a front seat that has an airbag. A newer airbag technology is called dual-stage front air bags. These adaptive systems can detect whether or not the seat belt is fastened, as well as the severity of a crash. In a low-level collision, the system inflates the front air bags less aggressively--with 70 to 80 percent of the force of a single-stage air bag. In a higher-speed collision they inflate with full force, providing firmer protection. The best air-bag systems can detect the presence, height, and seat position for the driver and front passenger, and deactivate or de-power front air bags as appropriate to minimize the chance of injury to out-of-position occupants or children. So, it is good to no that not all airbag systems are equal, and worth some research when looking for a used car.
Side-impact air bags have become more common and affordable in the past few years. A newer used car is likely to have these. Side airbags have been greatly improved since they first started to be installed, and they now protect not only the torso, but also the head. Side-curtain bags, the most common type, spread across both front and rear side windows to prevent occupants from hitting their heads and to shield them from flying debris. A curtain bag can also keep people from being ejected during a rollover. Finding a used car with side-impact airbags would be a real plus, as this technology has proven to really make a difference.
Telematics
Global Positioning Satellite (GPS) and cellular phones are combined in this technology. It can be found in certain brands of used cars. GM was the first manufacturer to use this with its OnStar service, followed later by Mercedes-Benz's TeleAid, BMW Assist, Volvo OnCall, and Lexus Link. All use the same technology and offer basically the same services. The driver can communicate with a central dispatch center, where the location of the vehicle can be tracked on a computer monitor to provide route directions or emergency aid. If a vehicle is in an accident the system automatically notifies the dispatch center, locates the vehicle, and sends emergency aid if the driver does not respond to an inquiry. A phone call to the dispatch center can find a "lost" car in a parking lot by beeping the horn, or unlock the doors if the keys have been misplaced. This technology offers not only convenience, but safety and security. Telematics can be found on later model used car. Note that a monthly service fee is usually required.
Traction control
This safety feature limits wheel spin during acceleration so that the drive wheels have maximum traction. It's particularly useful when starting off in wet or icy conditions. If the system detects wheelspin while accelerating on a slippery surface, it momentarily applies the brakes to the slipping wheel. This stops the slipping and automatically routes power to the opposite drive wheel. This can be the difference in crashing out of control and regaining control, and it is a desirable feature to have in a used car.
Antilock brakes
Without antilock brakes (ABS) you can't steer if the wheels lock up, and locked wheels can cause a vehicle to slide sideways. ABS prevents this from happening. Antilock brakes use wheel-speed sensors at each wheel and a computer. By preventing lock-up, ABS allows the driver to retain steering control while braking. ABS has become standard in vehicles, and should be easy to find when searching for your used car.
Electronic stability control
This system helps keep the vehicle on its intended path during a turn, and avoids sliding or skidding. It uses a system of sensors and a central computer. If the car starts to drift, the stability-control system momentarily brakes one or more wheels and, depending on the system, reduces engine power to keep the car back on course. Electronic stability control started on luxury cars and has expanded to SUVs and many other vehicles.
Safety-belts
While seatbelts can be found in all used cars, unless it is an antique, new technologies have made safety-belts even more effective. Adjustable upper anchors take into account the size of a person, and help position the belt across the chest instead of the neck to prevent neck injuries. Seatbelt pretensioners automatically retract the belts to take up slack during a frontal impact. This also helps position occupants properly to make a deploying airbag safe.
LATCH
Anyone who has young children and is searching for a used car should look for one with the LATCH system. It comes standard on many newer vehicles and should not be hard to find. The system features built-in lower anchors and top-tether attachment points allowing LATCH-compatible child safety seats to be installed without using the vehicle's safety-belt system. It is a nice alternative to the typical struggle of getting a baby seat tight using a seatbelt, although not all seats work with this.
Tire-pressure monitor
A tire can lose air very slowly, to the point that it is not noticeable. Yet, over time, the tires will become under inflated. This not only hurts fuel economy, but it also effects handling and can cause irregular tire wear – which can lead to a blowout. A government regulation requires vehicles made after October 31, 2006 to have a low-tire-pressure warning system. There are different types of systems which use different methods, and they are not all equal. When looking at a used car, this is something that should be looked into.