Toyota 2008 Prius Quick Reference Manual page 196

2-4. Using other driving systems
CAUTION
n To avoid operating the cruise control by mistake
Keep the "ON-OFF" button off when not in use.
Situations unsuitable for cruise control
n
Do not use cruise control in any of the following situations.
Doing so may result in control of the vehicle being lost and could cause seri-
ous or fatal accident.
In heavy traffic
l
On roads with sharp bends
l
l On slippery roads, such as those covered with rain, ice or snow
On winding roads
l
l On steep hills
Vehicle speed may exceed the set speed when driving down a steep hill.
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