Dodge 2013 Dart Owner's Manual page 115

Rear Monitoring
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
UNDERSTANDING THE FEATURES OF YOUR VEHICLE 113
between the two vehicles is greater than 10 mph
(16 km/h), the warning light will not illuminate.
Overtaking/Approaching
3