Jeep Grand Cherokee 2012 Owner's Manual page 217

Offset Driving
ACC may not detect a vehicle in the same lane that is
offset from your direct line of travel. There will not be
sufficient distance to the vehicle ahead. The offset vehicle
may move in and out of the line of travel, which can
cause your vehicle to brake or accelerate unexpectedly.
UNDERSTANDING THE FEATURES OF YOUR VEHICLE 215
Turns And Bends
When driving on a curve with ACC engaged, the system
may decrease the vehicle speed and acceleration for
convenience reasons, with no target vehicle detected.
Once the vehicle is out of the curve the system will
resume your original Set Speed. This is a part of normal
ACC system functionality.
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