New technology was among the reasons for the rise in speeding, concluded Frantz. Suspension systems were getting more advanced, coping with bumps better, and engines were more refined and potent. Consequently, it was far easier for a driver to unknowingly achieve an 'excessive rate'.
The solution proposed by Frantz was a 'speed control device' that would allow a driver to more easily and efficiently maintain a vehicle's speed. It would need to be easily overridden, so the driver could take control when required, and function unobtrusively.
All required the driver to keep their foot on the pedal and couldn't function unassisted, but many basic cruise concepts - including overriding the target speed by accelerating - were established by Frantz. Seemingly, despite receiving a patent in 1937, he took his idea no further. This was presumably because, at the time, he was otherwise fully occupied establishing a new company to design and produce magnetic separators for industrial applications.
Later, in May 1942, fuel rationing was enforced in 17 states in America to aid the war-related demands on the country's resources. By the end of 1942, fuel was rationed in all 50 states. The rationing of this vital lifeblood wasn't driven by an outright requirement to just preserve fuel, however - it was also designed to cut down America's rubber consumption.
Because Japan had taken control of Southeast Asia's rubber-producing zones - which had previously supplied the Allies - America was sorely lacking in the rubber necessary for the production of military vehicles and equipment. Synthetic rubber production was limited, too, so ways to prevent wastage were quickly brought into play. Less fuel meant less civilian travel, for starters, reducing consumption of both fuel and rubber.
Similarly, a nationwide 'Victory' speed limit of 35mph was introduced to reduce both tyre and fuel consumption. Many disliked the lower limits, however, either finding them incredibly boring or difficult to stick to.
Teetor, reputedly due to the low 'Victory limit' that many struggled to maintain and the need to save resources, set about working on a speed control system. This was later stated by his daughter; the story was originally that Teetor, who had been blind since a young age, disliked the rocking motion experienced when drivers continually changed their speed - which motivated him to develop a speed control system.
It took some time for him to develop a reliable system, in any case, and he finally submitted a patent - which referenced Frantz's earlier work - in August 1948. It was granted two years later and, following several further years of development, the Perfect Circle 'Speedostat' was born. The first production set-up was introduced in 1957 and, in 1958, it graced the Chrysler Imperial - in which it was dubbed 'Auto-pilot'.
Other manufacturers soon began buying the Speedostat and rebranding it for use in their cars; Cadillac called it 'Cruise Control', Chevrolet 'Speed and Cruise Control', and both Lincoln and Mercury named it 'Speed Control'.
It is worth mentioning that both Frantz and Teetor's approaches were indirectly preceded by some older technology, including a set-up found in the Wilson-Pilcher automobile of the early 1900s - which featured a governor-controlled engine. This, effectively, would maintain a set engine speed and function as a rudimentary form of cruise control. As Teetor had observed, however, these set-ups had issues that included definite speed limitations, the requirement to disable the governor to exceed set speeds and a limited degree of flexibility.
When the oil crisis of 1973 struck, manufacturers touted the fuel-saving potentials of cruise control systems - which were offered by several companies by this point - and the system subsequently flooded into the wider market.