The first car with Teetor's "Speedostat" system was the 1958 Imperial (called "Auto-pilot") using a speed dial on the dashboard.[3] This system calculated ground speed based on driveshaft rotations off the rotating speedometer-cable, and used a bi-directional screw-drive electric motor to vary throttle position as needed. It was Cadillac Division that re-named the "Speedostat" and marketed the device as "Cruise Control."[2]