Lexus GS430 User Manual page 420

Dynamic radar cruise control should not be used in the
following conditions, to avoid death or serious injury.
D In bad weather (such as rain, fog, snow, sandstorms,
or when raindrops or snowflakes get in the millimeter
wave radar sensor or
vehicle−to−vehicle distance will not be measured
accurately.
If the wipers are operated at high speed (including the
high speed operation with the wiper lever in the
"AUTO" position), dynamic radar cruise control is
automatically cancelled. (In the case of the low speed
operation and intermittent wiper operation, it is not
cancelled.) Dynamic radar cruise control is
automatically cancelled when the measurement is
extremely unstable due to bad weather.
D On the roads in heavy traffic or at sharp bends:
As an appropriate speed cannot be maintained, death
or serious injury could result.
D On slippery road surfaces (icy or snow−covered road
surfaces):
The tires will race and you will be unable to control.
D On steep downhill slopes:
If there is no vehicle detected ahead, the preset speed
will be easily exceeded because of inefficient engine
braking, resulting in death or serious injury. (In this
the cover), the case, automatic braking will not work.) If there is a
vehicle detected ahead, the delay in deceleration
timing could cause death or serious injury.
D When the warning tone sounds frequently (because
acceleration or deceleration was repeated or
sufficient vehicle−to−vehicle distance was not
maintained), an appropriate vehicle speed cannot be
attained, resulting in death or serious injury.
D On roads with steep and short inclines and declines,
failure to detect the vehicle ahead will shorten the
distance between your vehicle and the vehicle ahead,
resulting in death or serious injury.
STARTING AND DRIVING
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