2011 Cadillac DTS Owner's Manual - Page 179

When following a vehicle and entering a curve, ACC could lose track of the vehicle in your lane and accelerate your vehicle. When this happens the Vehicle Ahead symbol will not appear. 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. 4-21