The areas that vehicles can be detected in are outlined below.

To give the driver a more consistent time to react, the buzzer can alert for faster vehicles from farther away.
Example: 
The rear cross traffic alert function is operational when
Conditions under which the rear cross traffic alert function will not detect a vehicle
The rear cross traffic alert function is not designed to detect the following types of vehicles and/or objects.
*: Depending on conditions, detection of a vehicle and/or object may occur.
Conditions under which the rear cross traffic alert function may not function correctly
The rear cross traffic alert function may not detect vehicles correctly in the following conditions:

The rear cross traffic alert function
Driving tipsSun visors and vanity
mirrors
Sun visors
Forward position:
flip down.
Side position:
flip down, unhook, and swing
to the side.
Side extender (if equipped):
place in side position then slide
backwards.
Vanity mirrors
Slide the cover to open.
The light turns on when the cover
is opened.
Notice
To ...
Problem symptoms table
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms are
listed in order of probability in the "suspected area" column of
the table. Check each symptom by checking the suspected
areas in the order they are listed. Replace p ...
Installation
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the lh side.
Install front door belt moulding
assembly lh
Attach the claws to install the belt moulding.
Hint:
Confirm that the moulding is firmly installed.
Install outer r ...