Adaptive Automatic Transmission
Some transmissions can “learn” and adapt to the driver’s style, altering shift points and other transmission functions to produce the most efficient operation.

Adaptive Cruise Control
One step beyond cruise control, adaptive cruise control uses a radar sensor mounted in the front of the vehicle to maintain a safe cruising distance between your vehicle and the vehicle in front of you. Most systems allow you to set the interval (distance between vehicles) and will then accelerate and brake (within reason) to maintain that interval. In many cases, the systems can take into account hilly terrain and passing situations. All have the ability to act like regular cruise control, and they still require the driver to steer the vehicle normally. Some automakers refer to it as “intelligent” cruise control.

Adjustable Suspension
Provides better ride or handling. A variety of systems are used to vary shock-absorber firmness. Some automatically sense road conditions and adjust shock-absorber settings accordingly. Others include a switch on the dashboard or console that allows the driver to adjust shock-absorber settings to provide a softer or firmer ride, or sharper handling.

Air Suspension
Instead of steel coil or leaf springs, some vehicles have a bellows-like unit at each corner that contains pressurized air. As a rule, air suspensions can produce a softer ride.

Alternator
Alternators are used in modern automobiles to charge the battery and to power a car’s electric system when its engine is running. Alternators have the great advantage over direct-current generators of not using a commutator, which makes them simpler, lighter, less costly, and more rugged than a DC generator. The stronger construction of automotive alternators allows them to use a smaller pulley so as to turn faster than a DC generator, improving output when the engine is idling.

Anti-Lock Brakes (ABS)
Helps maintain control in emergency stops. Particularly useful on slick pavement. While the driver applies steady pressure to the brake pedal, the system automatically “pumps” the brakes many times per second to prevent wheel lock-up.

Antiskid System

Helps maintain control in fast turns. Works whether or not the brakes are applied. Sensors automatically apply individual brakes to prevent a sideways skid. Some systems also cut back on the throttle, slowing the engine. It’s also known as an electronic stability system or stabilization program.

Automatic Climate Control
A heating and air conditioning system that adjusts itself as needed, to maintain a pre-set temperature.

Automatic Transmission With Manual-Shift Capability
Allows manual gear changes, when desired, in an automatic transmission. Functions as a traditional automatic transmission when left in Drive, but includes a slot in which the shift lever can be moved to change gears manually. Sometimes, buttons for shifting manually through the gears are located on the steering wheel. This affords some of the advantages of a manual transmission, such as greater control of engine speed for better throttle response, but eliminates the need for a clutch pedal.

Bluetooth Capability
The ability of a radio system to work with Bluetooth wireless connectivity, to function in concert with a cellular phone.

Ball Joint
Ball joints are spherical bearings that connect the control arms to the steering knuckles. More specifically, a ball joint is a steel bearing stud and socket enclosed in a steel casing. The bearing stud is tapered and threaded. It fits into a tapered hole in the steering knuckle. A protective encasing prevents dirt from getting into the joint assembly.

Brake Assist
Designed to shorten stopping distance in a “panic” stop. Applies full braking power even if the brake pedal is not fully depressed. Sensors gauge the speed at which the driver initially depresses the brake pedal and determine whether full emergency stopping power is warranted.

Brake discs
The disc brake or disk brake is a device for slowing or stopping the rotation of a wheel. A brake disc (or rotor), usually made of cast iron or ceramic composites (including carbon, kevlar and silica), is connected to the wheel and/or the axle. To stop the wheel, friction material in the form of brake pads (mounted on a device called a brake caliper) is forced mechanically, hydraulically, pneumatically or electromagnetically against both sides of the disc. Friction causes the disc and attached wheel to slow or stop.

Continuously Variable Transmission (CVT)
Operates like an automatic transmission, with no need for a clutch pedal, but contains no gears. Instead, power is transmitted in a continuous flow from the engine to the drive wheels.

CV Boot
Allow a rotating shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. They are mainly used in front wheel drive and  all wheel drive cars. However, rear wheel drive cars with independent rear suspensions typically use CV joints at the ends of the rear axle halfshafts. Audi Quattros use them for all four half-axles and on the front-to-rear driveshaft (propeller shaft) as well, for a total of ten CV joints.

Curtain Side Airbags
Designed to cushion and protect occupants’ heads. Located on both the left and right sides of the vehicle, curtain side airbags deploy from above the front and rear side windows in a side-impact collision. Advanced systems deploy the bags when sensors detect an impending rollover. The bags inflate within a fraction of a second and deflate after a few seconds. They also help shield occupants from broken side glass. In some vehicles with three rows of seats, the curtain airbags do not reach backseat occupants.

Dual Front Airbags
Designed to protect the driver and front passenger in a frontal collision. Mounted in the steering wheel hub and in the right side of the dashboard, they inflate and deflate within a fraction of a second. Most systems can judge the severity of an impact and determine whether a front-seat occupant is wearing a safety belt or is out of position. This allows them to adjust the rate of deployment to minimize injuries from the airbags themselves. Dual front airbags are required by law on all new passenger vehicles.

Dual-Stage Airbags
Front airbags that can deploy at either of two levels, depending on the severity of a collision.

Dual-Zone Climate Control
Allows individualized control of heating and air conditioning. Most systems are adjustable for the driver and front passenger; others feature a third adjustment for rear passengers.

Drive Shaft
A drive shaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement between them.Drive shafts are carriers of torque: they are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, whilst avoiding too much additional weight as that would in turn increase their inertia.

Electronic Brake-Force Distribution
Operates in conjunction with ABS to balance the force applied to brakes at front and rear wheels. Can prevent over-braking, improve brake-pad life, reduce “brake fade” caused by excessive heat, and ensure peak braking efficiency in all conditions.

Fuel Injection
Fuel injection is a system for mixing fuel with air in an internal combustion engine. It has become the primary fuel delivery system used in gasoline automotive engines, having almost completely replaced carburetors in the late 1980s. A fuel injection system is designed and calibrated specifically for the type(s) of fuel it will handle. The majority of fuel injection systems are for gasoline or diesel applications.

Hybrid Powertrain
A propulsion system wherein a gasoline engine and electric motor work in concert. In some hybrid systems, electric operation is dominant; in others, the gasoline engine dominates. Only a few hybrid vehicles are available, but they promise greater fuel economy and reduced emissions.

Lane-Departure Warning System
Issues a warning when the vehicle edges off course and reaches the highway lane markers. Introduced on the 2005 Infiniti FX and available on the 2006 Infiniti M45, the system developed by Iteris can detect lane dividers even in rainy weather. It delivers a noticeable sound when the vehicle starts to move into an adjacent lane, whether due to inattention, drowsiness or distraction.

MP3 Capability
The ability of a radio to play computer-generated MP3 music, as well as CDs and/or cassettes.

Navigation System
An electronic map combined with route instructions, usually displayed on a dashboard video screen. The system communicates with a satellite to display, on the screen, the vehicle’s geographic location and direction of travel. Most systems let you input a destination using a keypad. A computer then calculates the best route and issues audible and visual directions to reach that destination. A few navigation systems lack a map, but provide vocal instructions. Some new systems operate with voice recognition, and are able to “understand” addresses and other oral instructions. Navigation systems are usually optional, though some luxury models have them as standard equipment.

Overhead-Cam Engine
In this configuration, the camshaft that drives the valve is located atop the engine rather than down inside. Engines with a dual-overhead-cam configuration have two separate camshafts rather than one.

Oversteer and Understeer
Any serious race fan knows the difference between “understeer” and “oversteer,” but ask for a description and they might get confused. Most front-wheel-drive cars will “understeer” (“push” or “be tight”) at the limit of adhesion, the point when the wheels lose their grip on the road. This condition is most noticeable in rain or snow. As you enter a corner and begin to turn the wheel, the car may try to go straight instead; and the harder you steer into the turn, the more the vehicle wants to continue to drive straight. You can help lessen the effects of understeer by lifting off the gas slowly and slightly applying the brakes. This will transfer more weight to the front wheels, allowing them to get more traction.

Most high-performance rear-wheel-drive cars will “oversteer” or become “loose” if you enter a turn too fast. The effect is similar to “doing donuts” in the high school parking lot after a snowfall. Oversteer is much more dangerous and difficult to correct. You have to first steer in the opposite direction to limit the slide of the car, and then you must be very gentle with the throttle and brakes to prevent the vehicle from going into a “snap” or violent spin.

Vehicle skid control systems can reduce understeer or oversteer, but they cannot change the laws of physics. Either way, it helps to know what to do when your car is at the limit of adhesion so you will react quickly and instinctively. It could save you thousands in a repair bill, or even your life.

Real-Time Traffic Information
Introduced on the 2005 Acura RL, this system can work with satellite radio to warn the driver if traffic conditions ahead are troublesome. It can then determine if an alternate route might be a better choice.

Rear Obstacle Warning System
Alerts the driver to unseen objects behind the vehicle when backing up. Sensors mounted in the rear bumper detect the presence of nearby objects. A tone or warning lights signal the distance to these objects. Some systems also warn of nearby objects in front.

Rear-Seat Entertainment System
Allows rear-seat passengers to view video. An option most often offered on mininvans and SUVs. Earlier entertainment systems played VHS video tapes, but most of the current ones play DVDs. Most have a screen that drops from the ceiling behind the front seats; others locate the screen near the floor between the front seats. The video/DVD player is mounted low in the dashboard or between the front seats or in the front center console. (A few vehicles, such as the Toyota Land Cruiser and Lexus LX 470, can play DVDs on their navigation system’s dashboard screen, but only when the vehicle is standing still.) Most systems allow front-seat passengers to listen to a separate audio source while those in back view videos. Remote controls for the video/DVD player, wireless headphones, and video-game ports and controls are typical accessories.

Satellite Radio
Two systems, XM and Sirius, provide radio reception via satellites rather than the customary broadcast method. Each service charges a monthly fee for delivering a large number of entertainment channels. Satellite-ready radios are standard in some vehicles and optional for many more.

Side Airbags
Designed to protect occupants in a side collision. Some side airbags are shaped to provide protection for just the torso, others for both the torso and head in a side collision. Some are mounted in the side of the seat backrest. Others are in the door panel. The bags inflate and deflate within fractions of a second. Side airbags can be furnished for both front- and rear-seat occupants.

Traction Control
Helps limit tire slip in acceleration on slippery surfaces. Sensors determine if the wheels that are receiving power have lost traction. The system automatically “pumps” the brake to those wheels to keep them from slipping. Some systems also reduce engine power to the slipping wheels.

Turbo Charging
Turbochargers make use of exhaust gases to compress the air that enters the engine, which increases its potential power output.

Variable Valve Timing
Using computer control, VVT alters the opening and closing of the engine’s valves automatically to produce the greatest level of efficiency. Ordinary engines have fixed valve operation.

Voice Recognition
Quite a few climate-control and other systems can respond to vocal commands. These systems are expanding into navigation systems as well. In Honda‘s redesigned 2005 Odyssey, for instance, the computer can understand a destination stated orally by the driver and calculate a route accordingly, with no need to use a keypad to enter a street or number.

Xenon Headlights
Also known as “high-intensity-discharge (HID)” and “bi-xenon” headlights. Standard on some vehicles and optional on others, they provide a brighter and more effective beam. On a few vehicles, the headlights can move laterally in concert with the steering wheel to illuminate the road ahead even in a curve.