The Blind Spot Monitor uses sensors to monitor the blind spot detection area and the area behind your vehicle and informs you via indicator lights in the outside mirrors. The system measures the distance to other vehicles and the difference in speed between your vehicle and other vehicles. The Blind Spot Monitor only works at speeds above about 9 mph (15 km/h). 
Indicator lights in the outside mirrors 
The indicator light ⇒ fig. 137 in the glass for the respective outside mirror informs you about traffic to the rear, if the system interprets the situation as critical. The indicator light in the driver side outside mirror A informs you about traffic to the left, and the indicator light in the passenger side outside mirror B informs you about traffic to the right of your vehicle. 
Tinting on the side windows or aftermarket tinting films can interfere with the indicator lights in the outside mirrors or cause false readings. 
Keep the glass in the outside mirrors clean and free of snow and ice, and do not cover the mirrors with stickers or other objects. 
Radar sensors 
The radar sensors are behind the rear bumper on the left and right ⇒ fig. 138. They are not visible from outside the vehicle. They monitor an area about 21 yards (20 meters) behind the vehicle as well as the blind spots on the left and right sides of the vehicle. The monitored area next to the vehicle is about one lane wide. 
The width of the lane is not detected individually on each road, but is preprogrammed into the system. Because of this, the indicators may be incorrect when driving on narrow roads or driving in the center of two lanes. Likewise, vehicles that are two lanes away from you or stationary objects such as guard rails may also be detected and cause a false warning. 
Driving situations 
 
Fig. 139 A: Driving situation when passing with traffic behind your vehicle. B: Blind Spot Monitor indicator light in the driver side mirror. 
 
Fig. 140 A: Driving situation when passing and merging into the lane. B: Blind Spot Monitor indicator light in the passenger side mirror. 
 
         
        
         
Automatic braking intervention 
If the Rear Traffic Alert detects an approaching vehicle and the driver does not press the brake pedal, the system can intervene with automatic braking. 
The Rear Traffic Alert assists the driver with harsh automatic braking that could help prevent or reduce damage that may result from a collision. The automatic braking occurs while backing up at speeds between 1–7 mph (1–12 km/h). Once the system detects that your vehicle is stationary, it keeps the vehicle from moving for up to 2 seconds. 
After an automatic braking intervention, about 10 seconds must pass before the system can brake automatically again. 
The driver can interrupt the automatic braking and take control of the vehicle by pressing firmly on the gas or brake pedal. 
  WARNING 
The Blind Spot Monitor with Rear Traffic Alert technology cannot overcome the laws of phys-ics and limits of the system. Careless or unintentional use of the Blind Spot Monitor and Rear Traffic Alert may result in accidents and serious injuries. 
 x The Rear Traffic Alert is not a substitute for careful and attentive driving. 
 x Never use the system when visibility is limited or in confusing traffic situations, for exam-ple, on heavily traveled roads or when there are multiple lanes. 
 x Always watch for people, especially small children, bicycles, animals, and objects, be-cause the Rear Traffic Alert may not always be able to detect them. Rear Traffic Alert cannot detect people, animals, and things that are moving slowly or not at all. 
 x The Rear Traffic Alert does not always brake the vehicle to a complete stop. 
 x The harsh automatic braking will be uncomfortable for many people, and if you or your passengers have special conditions or sensitivities, particularly in the neck, you may want to switch off Rear Traffic Alert. 
Using the Blind Spot Monitor with Rear Traffic Alert