The cruise control in your car is an electronic device that controls the speed of the vehicle, maintaining a steady set speed without the use of the gas pedal. The cruise control can be set at any speed selected by the driver and is disengaged by the push of a button or use of the brake. Newer models of cars can also have add-ons to the cruise control function that slow the car when it comes up on another vehicle that is going more slowly and sensors that alert the driver if there is another vehicle alongside the car. The cruise control in your car needs to be functioning properly to be used safely. If you're your vehicle is experiencing issues with its cruise control or if the cruise control has stopped working, you will want to replace it with the original system that was installed in the car by the manufacturer. Look for your BMW Z4 Cruise Control here.