MyKey® technology, standard in every Flex, lets you program individual keys so that two members of a household can share a car, yet have personalized settings take effect when they use their unique keys. MyKey is designed to help parents encourage teenagers to drive safely. It lets you to designate a key to operate special features, such as restricting the vehicle’s top speed to 65, 70, 75 or 80 mph and limiting the entertainment system’s audio to 44 percent of maximum volume. It also provides a warning when the fuel tank reaches 75 miles to empty, allows the owner to select speed alert chimes at 45, 55 or 65 mph, and sets the Belt-Minder® to chime, while muting the audio system, until the safety belt is buckled.