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 tipsCompressor and pulley (for 2az-fe)
Components
Removal
Discharge refrigerant from
refrigeration system (see page ac-172)
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensione ...
System description
Lighting system
Illumination control system (illuminated entry
system):
When the doors are unlocked by a key or
transmitter operation, or when a door is opened or
closed, the illuminated entry system turns on the
room light, map light, foot light and ignition key
cylinder light*1 o ...
Operation check
Inspect driver side seat belt warning light
Turn the ignition switch on.
When the driver seat belt is not fastened, check that
the driver seat belt warning light on the combination
meter blinks.
When the driver seat belt is fastened, check that the
driver seat belt warning light o ...