Cadillac 2005 XLR - Manual (Page 138)

Adaptive Cruise Control may detect a vehicle that is not
in your lane and apply the brakes.
Adaptive Cruise Control 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.
Highway Exit Ramps
{ CAUTION:
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 on exit ramps.
3-26