2012 Toyota Prius Owners Manual - Page 581

2-4. Using other driving systems Selecting conventional constant speed control mode Constant speed control mode differs from vehicle-to-vehicle distance control mode. When constant speed mode is selected, your vehicle will maintain a set speed regardless of whether or not there are other vehicles in the lane ahead. Press the "ON-OFF" button to activate the cruise control. Press the button again to deactivate the cruise control. Switch to constant speed control mode. (Push the lever forward and hold for approximately 1 second.) Cruise control indicator will come on. When in constant speed control mode, to return to vehicle-to-vehicle distance control mode, push the lever forward again and hold for approximately 1 second. After the desired speed has been set, it is not possible to return to vehicle-to-vehicle distance control mode. 278