(Another installment in our continuing series looking at how the cars of yesterday are being transformed into the driverless cars of tomorrow via the technology of today.)
While no one recognized it at the time, it could be that the first step toward autonomous vehicles was the advent of cruise control. With cruise control, motorists gain the ability to surrender a driving task to the automobile itself.
A Quick Look Back
Devices designed to maintain constant speed were first applied in automobiles as early as 1900. In 1948, a carsick passenger named Ralph Teetor invented what became modern cruise control. Apparently, Teetor was a frequent passenger in his lawyer’s car. To Teetor’s dismay, his attorney had the unconscious habit of speeding the car up and down as he talked.
As the decades passed, refinements and progress continued to be made to cruise control systems. In the early 1970s, cruise control became widely available and was marketed as a fuel saving device. All major American automakers offered this optional equipment beginning in 1974. The upgrade cost between $60 and $100 at a time when the average sticker price of a new car was in the neighborhood of $3500.
Traditional Cruise Control
Until recently, cruise control changed very little from that $60 option available in 1974. To activate it, the car is accelerated to the desired speed and, with the push of a button, the device is set to maintain that speed. The system is deactivated by a second push of the button or by a short tap on the brake. Use of cruise control affords nominal gas savings over long distances and eliminates the chance of a driver receiving a ticket from exceeding the posted speed limit due to inattention. The effectiveness of cruise control is constrained by changes in road surface condition and is impractical for use in situations where speed varies multiple times within a short distance.
Adaptive Cruise Control
With adaptive cruise control (ACC), the speed of the car is not maintained but regulated. As with traditional cruise control, the driver sets the desired speed but is also required to input a desired following distance. Using data about the car’s surroundings gathered by equipment such as cameras or even radar, the speed of the car is continuously adjusted to maintain the preset following distance to the vehicle ahead.
The advantages provided to the driver by this new speed sensitivity are obvious. The ability of the car to adapt to speed differences between vehicles ahead increases safety by increasing the available time to react to traffic conditions. In some cases, adaptive cruise control works in conjunction with automatic braking to expand this cushion of safety. ACC still has its limitations with regard to changes in road surface condition and, unlike traditional cruise control, can be negatively affected by adverse visibility.
It is important to remember that, as of this stage of automotive evolution, it is still the driver and his attentiveness that remain the number one key to crash avoidance. While we are moving toward a day when every rider in a car will be a passenger, we are not there yet.