In 1902, on a New York City streetcar on a particularly miserable day, weather-wise, Mary Anderson had a brainstorm. After watching the driver struggle to see out the window, only to receive snow in his face, Anderson wondered aloud why no one had ever done something to improve visibility in inclement weather. Upon being told that it had been tried and couldn't be done, Anderson began drawing diagrams for what would later become windshield wipers.
Engineers had already faced the problem of poor visibility in rain or snow, and come up with somewhat of a solution. They split the windshield in two, so that when the windshield became covered with rain or snow, the driver could open the middle for a clear view. This was the theory, but in practice, the split windshield did not work very well. When drivers opened the windshield, they received blasts of cold air, clumps of heavy, wet snow, or driving rain in their faces, none of which improved visibility. Some drivers actually smeared pieces of onions or other vegetables across the glass, hoping that the greasy film left behind would repel water.
As Mary Anderson watched one of these drivers struggle to see out the windshield and keep the passengers safe, she began thinking of a contraption with a lever on the inside to move an arm on the outside that would wipe off the rain or snow. She sketched out the idea of windshield wipers while on the streetcar.
When Anderson returned to her Birmingham home, she refined and added to her sketches. She then hired a manufacturing company in Birmingham to make a model of her windshield wipers. On her patent application, she stated, "My invention relates to an improvement in window-cleaning devices in which a radially-swinging arm is actuated by a handle from inside of a car-vestibule."
Her windshield wipers were made of wood and rubber, and were removable so that the streetcar appearance would not be compromised in good weather. She added a counterweight to maintain an even pressure on the windshield, and effectively wipe off snow and rain. She was awarded a patent in 1903 for a "window-cleaning device," or windshield wipers.
As soon as Anderson's windshield wipers were patented, she wrote to a large company in Canada offering them the rights. This company was not interested, stating that her invention had little, if any, commercial value and would not sell. They did tell her that they would be interested in any other, more useful, patents that she might have.
Anderson's patent was put away and eventually expired. Although Anderson never profited from her invention, it was re-examined soon after, and by 1913 mechanical windshield wipers were standard on domestic cars, including the Ford Model T. Cars became safer, as drivers could see out of the front window in any kind of weather.
In 1917, windshield wipers evolved when the "Electric Storm Windshield Cleaner," was patented by Charlotte Bridgewood. These were the first automatic windshield wipers. These windshield wipers got power from the car's engine and operated on rubber rollers, rather than blades. Her windshield wipers did not sell well, but both these women laid the groundwork for modern windshield wipers, which keep drivers and passengers alike much safer in rain or snow.