Toyota C-HR 2020 Manual page 281

RCTA function detection areas
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:
Approaching vehicle
Fast
Slow
C-HR_OM_USA_OM10634U
4-5. Using the driving support systems
Speed
18 mph (28 km/h)
5 mph (8 km/h)
281
Approximate
alert distance
65 ft. (20 m)
18 ft. (5.5 m)
4