Cadillac 2005 XLR Owner's Manual page 135

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.
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.
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