Haynes' car is believed to be the second gasoline-engine powered vehicle successfully road tested in the United States, according to its exhibit information at the Smithsonian Institution. It was built two years before Henry Ford's Quadricycle, and preceded only by Charles Duryea's Motorized Wagon less than a year earlier. Unlike Duryea's car, which was an adapted buckboard wagon that was designed to run under its own power but still able to be pulled by horse, Haynes' car was designed only to run on its own. Some automotive historians use this difference to determine that Haynes' car was the first true American automobile. The Sintz company continued to be intrigued by Haynes' use of their motor and sent representatives to photo his vehicle and published the images as an advertisement for one of their engine's possible uses. The publicity spurred the creation of numerous other automobiles across the American midwest.