Volvo, Ford, Infiniti and Audi all have advanced blind-spot detection methods. While these methods may vary from one manufacturer to the other, they all work to provide a safer driving experience.
Most auto manufacturers use a combination of light and noise to inform the driver that there is a car in the blind-spot. Each manufacturer has a different take on each system, using both or part of each. Luxury cars most commonly include blind-spot detection systems, but such systems are increasingly common in other markets.
Volvo uses an advanced detection system that it calls Blind Spot Information System. This system identifies blind-spot cars using either cameras or radar, depending upon the model year of the car. When a car appears in a blind-spot and the driver turns on a blinker in that direction, an LED in the A-pillar directly to the left of the driver's seat lights up to inform the driver that there is a car in the blind-spot.
Ford uses a similar system with radar near the rear of the car, but it places its warning lights in the side mirrors corresponding to the direction a potentially unseen vehicle is in. Audi also uses this system in its vehicles.
Infiniti uses a similar system as Ford and Audi, but it goes a step further. When drivers attempt to turn the car in the direction that the system detects a car in, a gentle brake is applied to the opposite side during the attempted turn. This causes the car to gently swerve away from the potential collision.