Lexus RX400h2006 Owner's Manual page 461

STARTING AND DRIVING
CAUTION
Braking control will not ensure that your vehicle will
reduce speed appropriately. You must depress the
brake pedal to slow down, in order to avoid a collision
or to maintain sufficient vehicle−to−vehicle distance.
434
(j) Approach warning
While you are cruising in the vehicle−to−vehicle distance
control mode, if the vehicle ahead decelerates abruptly or if
another vehicle cuts in ahead of you, your vehicle may come
closer to the vehicle ahead. The display will flash and beep to
alert you.
CAUTION
D If the display flashes and beeps, this indicates that
you must depress the brake pedal in order to slow
down sufficiently to avoid a collision or maintain
appropriate vehicle−to−vehicle distance.
D In the following conditions, the approach warning
may not turn on even if the vehicle drives closer to the
vehicle ahead, and an accident may occur:
Your vehicle and the vehicle ahead are cruising at
almost the same speed.
The vehicle ahead is cruising at a faster speed than
yours. (The distance between the vehicles will
become longer.)
The vehicle ahead is at a stop or driving very slowly.
Pay special attention to a very slow vehicle at the end
of the line in heavy traffic or at a tollgate.
The speed has just been set.
The accelerator pedal is depressed or has just been
released.