Cadillac 2010 DTS Owner's Manual page 189

ACC may detect a vehicle that is not in your lane and
apply the brakes.
ACC may, occasionally, provide a driver alert and/or
braking that you consider unnecessary. It could respond
to signs, guardrails, and other stationary objects when
entering or exiting a curve. This is normal operation.
Your vehicle does not need service.
Adaptive Cruise Control may lose track of the
vehicle ahead and accelerate up to your set
speed while entering or on highway exit ramps.
You could be startled by this acceleration and
even lose control of the vehicle. Disengage
Adaptive Cruise Control before entering a
highway exit ramp. Do not use Adaptive Cruise
Control while entering or on exit ramps.
If another vehicle enters the same lane as you, ACC will
not detect the vehicle until it is completely in the lane.
Be ready to take action and apply the brakes yourself.
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