2004 Cadillac XLR Owner's Manual - Page 128

Approaching and Following a Vehicle The vehicle ahead symbol will only appear on the HUD when a vehicle ahead is detected in your path. {CAUTION: When the ACC radar is blocked by snow, ice, or dirt, it may not detect a vehicle ahead until it is very close. ACC may not have time to slow your vehicle enough to avoid a collision. Do not use ACC when the radar is blocked by snow, ice, or dirt. Keep your radar clean. See "Cleaning the System" later in this section. ACC will automatically slow your vehicle down when approaching a slower moving vehicle. ACC 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 never exceed the set speed. ACC 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. If this symbol does not appear, or disappears briefly, ACC will not respond to vehicles you may see ahead. 3-18