F1 MachineThe F1 Machine was a Honda powered Lotus 99T, which was driven by Ayrton Senna, and Satoru Nakajima. With the help of Senna, the car won two Grands Prix, and six other podium finishes in 1987. The Lotus was sponsored by Camel cigarettes, which did not appear in the game to not much surprise.
Power GloveRad Racer is also compatible with the Power Glove! To see in action, see the movie The Wizard.
ReferencesFor those who are fans of Homestar Runner, the level 1 theme music in this game (when you're winning) is the theme music given to "Stinkoman", also known as the anime Strong Bad.
SpeedometerIn Rad Racer the top speed any car can attain is 255 km/h. In the sequel, the top speed is 255 mph. So technically, the car can go around 100 miles faster in the sequel. Also note on the game's US cover that the picture depicts mph while the game features km/h.
TitleThe name Rad Racer was used in North America. In Japan, the game is called Highway Star, a name already used by the music band Deep Purple, and Square could not get Deep Purple's permission to use the name of the game. In the US version when choosing the car you want to use, there is still an HS next to the car that you want to pick.
Information also contributed by Alaka, DOS Boot, Scott G, and Robbb