Acura 2011 RL Owner's Manual page 328

Adaptive Cruise Control (ACC)
If the vehicle ahead of you slows
down abruptly, or if another vehicle
cuts in front of you, a beeper sounds
and a message appears on the multi-
information display to warn you.
In this case, decelerate your vehicle
by pressing the brake pedal, and
keep an appropriate distance from
the vehicle ahead.
322
When a vehicle ahead is within ACC
range and going at a steady speed
Your vehicle follows the vehicle
ahead of it, keeping a constant
distance. ACC will not keep your
vehicle at a constant distance if the
vehicle ahead of you goes out of
range of your set speed.
If the vehicle ahead of you slows
down and changes lanes, ACC no
longer tracks it. Your vehicle will
then return to your set speed.