Many variations of braking systems have evolved over the years. Some have been more successful than others depending on the distance required to stop, the speed of the vehicle, and the person operating the brake.

The first truly effective and reliable brakes were made for trains and were patented by George Westinghouse in 1869. He was met with great resistance, however, from railroad brakemen who made their living by listening for whistle signals from the engineer. Westinghouse's brake was originally activated by opening valves to release compressed air into tubes that ran the length of the train. He soon realized, however, that a leak or break in the lines rendered the entire system ineffective. In 1872, he improved the mechanism so that air pressure held the brake open until it was released.

While steam, compressed air, vacuum, and hydraulic brakes were all in use in various kinds of...