Chrysler Town & Country 2011 Owner's Manual page 127

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).
Rear Monitoring
UNDERSTANDING THE FEATURES OF YOUR VEHICLE 125
Overtaking Traffic
If you pass another vehicle slowly (with a relative speed
of 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.
Overtaking/Approaching
3