Dodge 2014 Dart Owner's Manual page 129

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 127
Overtaking Traffic
If you pass another vehicle slowly (with a relative speed of
less than 15 mph (24 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 15 mph (24 km/h), the warning
light will not illuminate.
Overtaking/Approaching
3