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 tipsReassembly (2005/11-2006/01)
Install drive shaft bearing case subassembly
Using sst and a press, press in the drive shaft
bearing case to the inboard joint rh.
Sst 09527-10011, 09710-04081
Notice:
The bearing should be installed completely.
Using a snap ring expander, install a new drive shaft
hole ...
Engine immobilizer system
The vehicle's keys have
built-in transponder chips
that prevent the engine from
starting if a key has not
been previously registered
in the vehicle's on-board
computer.
Never leave the keys inside
the vehicle when you leave
the vehicle.
This system is designed to
help prevent vehicle theft but
does ...
Problem symptoms table (2005/11-2006/01)
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 ...