Chrysler 2009 Country - Owner Manual - Manual (Page 112)

Entering From The Rear
Vehicles that come up from behind your vehicle on either
side and enter the rear detection zone with a relative
speed of less than 30 mph (48 km/h). Overtaking Traffic
If you pass another vehicle slowly (with a relative speed
less than 10 mph (16 km/h) and the vehicle remains in
the blind spot for approximately 1.5 seconds, the warning
light will be illuminated. If the difference in speed
between the two vehicles is greater than 10 mph
(16 km/h), the warning light will not illuminate.
Rear Monitoring
110 UNDERSTANDING THE FEATURES OF YOUR VEHICLE