R-X

Real-Time Traffic Information

This system works with satellite radio to warn the driver if traffic conditions ahead are troublesome. It may 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 minivans, crossovers, and SUVs. Earlier entertainment systems played VHS videotapes, but the current ones play DVDs. Some have a screen that drops from the ceiling behind the front seats; others locate the screen near the floor between the front seats; and some offer seat-back screens for in-your-face viewing. The video/DVD player is mounted low in the dashboard or between the front seats or in the front center console. Some systems allow front-seat passengers to listen to a separate audio source while those in back view videos. Remote controls for the DVD player, wireless headphones, and video-game ports and controls are typical accessories.

Satellite Radio

Systems such as Sirius XM provide radio reception via satellites rather than the customary AM/FM 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.

Stability-Control System

See "Antiskid System."

Traction Control

Helps limit tire slip during 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.

Turbocharging

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

In some navigation systems, such as Ford Sync, the computer can understand a destination stated verbally 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.