Cross Traffic Alert is only available for vehicles with Blind Spot Assist or Active Blind Spot Assist.
Cross Traffic Alert can warn drivers of any crossing traffic when reversing and manoeuvring out of a parking space. The radar sensors in the bumper also monitor the area adjacent to the vehicle. If a critical situation is detected, the 
symbol appears in the media display and the vehicle can be braked automatically.
If the radar sensors are obstructed by vehicles or other objects, detection is not possible.
if the vehicle is reversing at walking pace.
manoeuvring assistant is activated More.
Also observe the instructions on Blind Spot Assist and Active Blind Spot Assist More.
Cross Traffic Alert is not available on inclines.
Cross Traffic Alert is not available when driving with a trailer.