In a visit to New York City in the winter of 1903, in a trolley car on a frosty day, she observed that the motorman drove with the front window open because of difficulty keeping the windshield clear of falling sleet. When she returned to Alabama she hired a designer for a hand-operated device to keep a windshield clear and had a local company produce a working model. She applied for, and in 1903 was granted, a 17-year patent for a windshield wiper. Her device consisted of a lever inside the vehicle that controlled a rubber blade on the outside of the windshield. The lever could be operated to cause the spring-loaded arm to move back and forth across the windshield. A counterweight was used to ensure contact between the wiper and the window. Similar devices had been made earlier, but Anderson's was the first to be effective.
In 1905 Anderson tried to sell the rights to her invention through a noted Canadian firm, but they rejected her application saying "we do not consider it to be of such commercial value as would warrant our undertaking its sale." After the patent expired in 1920 and the automobile manufacturing business grew exponentially, windshield wipers using Anderson's basic design became standard equipment. In 1922, Cadillac became the first car manufacturer to adopt them as standard equipment.