Infrared

Other alternatives for control involve the use of either IR or RF connected remote controls for hands-only, driving-friendly control.

Another notable mention, although technically a software more than hardware, but a very versatile & popular interface option is girder, which will allow almost unlimited control integration of hardware to software control. It will allow you to custom program a remote control, or integrate many different possibilities of hardware button controls, from a custom built button interface using anything from a keyboard matrix to a simple keypad, girder is worth checking out if you're after custom controls.