Car Features

The man who invented cruise control


In many lists of little-known automotive historical facts is a tidbit about the engineer who invented cruise control: he was actually blind. Yeah, that seems pretty incredible, but that’s where the info about Ralph R Teetor begins and ends for most.


 Ralph R Teetor – Smithsonian


That’s sad, because the life Teetor lived was inspirational and rich, as he left an indelible mark on the automotive industry that extended far beyond just the creation of cruise control.

Born in Hagerstown, Indiana, USA in 1890, Ralph Teetor wasn’t blind at birth. He spent part of his childhood in Victorian rural Indiana, with the full use of all his senses. However, an accident with a knife at the age of five left him completely blind. 

His deeply religious parents didn’t allow Ralph to feel sorry for himself: an attitude he adopted himself. Pulling himself up by his bootstraps, the boy learned to do what everyone else who could see did, including attending college. There was no shortage of doubters, although they were quickly won over once they saw him in action.   

From a young age, Ralph had an intense interest in the work his father and uncles performed as they created maintenance cars for the railroads. He learned to work lathes, grinders and other dangerous machines in the shop, without serious injury. In fact, after a while many of the men remarked how proficient the blind boy was with their tools of trade.   

Ralph further proved his wherewithal in college, which he completed with the help of a cousin. However, life took him back to the family business, which had transitioned to making components for automobiles. Because the business started to focus mainly on piston rings, the name was changed to Perfect Circle – a brand you might recognise.   

Just by listening to an engine, Ralph Teetor could correctly diagnose a mechanical problem. He was famous for this, resulting in his working with several people in the automotive industry to diagnose issues, including motorsport teams. You could say he was a car whisperer of sorts.

Of course, his most famous contribution to the automotive industry was the invention of cruise control. 

In the USA, fuel and tyre rationing during WWII was enforced by a national speed limit of 35mph that originally got him thinking of how to help people maintain a constant speed over long distances. Also, while riding as a passenger in a car driven by his patent attorney, who kept speeding up and slowing down every time he talked, Ralph realised a device that could regulate speed could improve road safety.

Having been a pioneer of automatic transmission, Teetor was already experienced with vehicle mechanisms, so he set about designing a solution to the problem.


Ralph Teetor (right), cruise control in hand, with William Prossner, president of Perfect Circle, in 1957 – Automotive Hall of Fame


The result was a system that calculated ground speed based on the rotations of the vehicle’s driveshaft and used a bi-directional screw-drive electric motor to vary throttle position as needed. Once the vehicle achieved the selected speed, a governor overcame spring tension to actuate a vacuum-driven piston, which in turn pushed against the accelerator pedal. 

On August 11, 1948, Teetor filed a patent application for a ‘speed control device for resisting operation of the accelerator’. That patent was granted on August 22, 1950 and cruise control as we know it was born.


In the early days, the ‘Speedostat’ (Ralph hated the name ‘cruise control’ suggested later by Cadillac) featured a dashboard-mounted speed selector.

Although the patent for this amazing invention was filed in 1948, it wasn’t until the oil crisis of the 1970s that it really caught on. With a national speed limit put in place to help conserve fuel and law enforcement vigorously enforcing it, people clamoured for the device that would keep them out of trouble.

Modern electronically-actuated cruise control systems began to emerge in the 1990s, with manufacturers incorporating more advanced digital technology into the design. Other systems such as LiDAR, radar, sonar and camera-based solutions were soon added, increasing the car’s ability to sense oncoming traffic, which in turn helped the vehicle to determine speed and avoid potential accidents.

Many other patents were filed by Ralph R Teetor, including one for a hydraulic automatic transmission; an improved piston for controlling heat expansion; a mechanism for dynamically balancing steam turbines in US Navy ships;  a pistol-grip fishing rod handle; an easier-to-use doorknob; a better lawn mower; an easier-to-use door lock and a suitcase in which to fit more clothes without wrinkling them.   

His daughter said he was always tinkering in the basement at night, with the lights off, as his mind worked on all kinds of problems. The man had an unceasing desire to improve the quality of life for everyone around him, which he did.

Throughout his life, Ralph Teetor counselled many other blind people, including war veterans who lost their sight in service to their country. He always told them to not feel sorry for themselves and to work smart as well as hard, that in so doing they could accomplish great things in their life.

The man absolutely practiced what he preached, as he didn’t let his lack of sight hold him back in the least.

Ralph Teetor died in 1982 and, six years later, was posthumously inducted into the Automotive Hall of Fame in Dearborn, Michigan, for his numerous contributions to the automotive industry.


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