Cruise control

Modern cruise control (also known as a speedostat or tempomat) was invented in 1948 by the blind inventor and mechanical engineer Ralph Teetor.

A more significant factor in developing cruise control was the 35 mph (56 km/h) speed limit imposed in the United States during World War II to reduce gasoline use and tire wear.

[5] A mechanism controlled by the driver provided resistance to further pressure on the accelerator pedal when the vehicle reached the desired speed.

[5] Teetor's idea of a dashboard speed selector with a mechanism connected to the driveshaft and a device able to push against the gas pedal was patented in 1950.

The first car with Teetor's "speedostat" system was the 1958 Chrysler Imperial (called "auto-pilot"), using a speed control dial on the dashboard.

[9] This system calculated ground speed from the rotating speedometer cable and used a bi-directional screw-drive electric motor to vary the throttle position as needed.

Daniel Aaron Wisner invented an "automotive electronic cruise control" in 1968 as an engineer for RCA's Industrial and Automation Systems Division in Plymouth, Michigan.

All cruise control systems must have the capability to be turned off explicitly and automatically when the driver depresses the brake pedal and often also the clutch.

When the cruise control is engaged, the throttle can still accelerate the car, but once the pedal is released, it will slow down the vehicle until it reaches the previously set speed.

However, they will not apply the brakes in the event of overspeeding downhill, nor stop the car from going faster than the selected speed even with the engine just idling.

Many systems also incorporate cameras, lasers, and millimeter-wave radar equipment to determine how close a vehicle is to others or other objects on the roadway.