Dodge 2013 Dart Owner's Manual page 113

UNDERSTANDING THE FEATURES OF YOUR VEHICLE 111
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
3
light will not illuminate.
Overtaking/Passing
Overtaking/Approaching