Chrysler 300 2018 Owner's Manual page 157

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
The BSM system is designed not to issue an alert on
stationary objects such as guardrails, posts, walls, foliage,
berms, etc. However, occasionally the system may alert on
such objects. This is normal operation and your vehicle
does not require service.
Overtaking/Passing
SAFETY 155
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