Jeep 2014 Grand Cherokee Owner's Manual page 138

136 UNDERSTANDING THE FEATURES OF YOUR VEHICLE
between the two vehicles is greater than 15 mph
(24 km/h), the warning light will not illuminate.
Overtaking/Approaching
Overtaking/Passing
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.