2008 Toyota Prius Owners 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. n Situations unsuitable for cruise control 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 serious or fatal accident. l In heavy traffic l On roads with sharp bends l On slippery roads, such as those covered with rain, ice or snow l On winding roads l On steep hills Vehicle speed may exceed the set speed when driving down a steep hill. 166 PRIUS_U_(L/O_0802)