While the car resembles Sam Speed's original Speed Team vehicle, the Rocket Car has a much more sleek design and is built with a lot of modern features. True to its name, the Rocket Car's most notable feature is its powerful super rocket engine (called the "SSIII") which enabled it to propel at speeds that almost match Sonic's supersonic speed.
The Rocket Car can hover above the ground while moving, though it has retractable wheels it can deploy. Curiously, it also has a spring attached to the back of the car that would launch away those who stand on it as demonstrated by Sonic.
According to Sam, the SSIII super rocket engine for the Rocket Car was designed by the world's leading engineers at the Department of Science and Technology and over one billion dollars was spent into the development of the project. After the Rocket Car was finished, the President wished for Sam to use it in a road race against Sonic to increase his popularity for the next government election. With it, Sam arrived at the Thorndyke Mansion to challenge Sonic. After a long process of persuasion, Sonic accepted and the race finally occurred. While Sam got off to a rocket start, Sonic managed to stay neck and neck with Sam most of the time.
As the race drew to the end, Sam used the full extent of the SSIII super rocket engine to take the lead, but Sonic caught up with him and easily reached the finish first (though it took some photos to reveal it).