Cadillac 2007 XLR Owner's Manual page 158

Approaching and Following a Vehicle
If this symbol does not appear, or disappears
briefly, Adaptive Cruise Control will not respond to
vehicles you may see ahead.
158
The vehicle ahead
symbol will only appear
on the HUD when a
vehicle ahead is
detected in your path.
CAUTION:
{
When the Adaptive Cruise Control radar is
blocked by snow, ice, or dirt, it may not
detect a vehicle ahead. Adaptive Cruise
Control may not have time to slow your
vehicle enough to avoid a collision. Do
not use Adaptive Cruise Control when the
radar is blocked by snow, ice, or dirt.
Keep your radar clean. See "Cleaning the
System" later in this section.
Adaptive Cruise Control will automatically slow
your vehicle down when approaching a slower
moving vehicle. It will then adjust your speed to
follow the vehicle in front at the selected follow
distance. Your speed will increase or decrease to
follow the vehicle in front of you but will not
exceed the set speed. The system may apply
limited braking if necessary. When braking
is active, your brake lights will come on. It may
feel or sound different than if you were applying
the brakes yourself. This is normal.