Interstate '76: Nitro Pack (also known as Nitro Riders) is a stand-alone expansion/prequel to Interstate '76 that introduced new characters, over a dozen new vehicles, and new multiplayer modes.
The single-player portion of the game includes the "Auto Melee" (deathmatch versus AI) mode of the original, but instead of the storyline-based T.R.I.P. mode of the original, Nitro included a number of smaller independent scenarios featuring four different characters, Taurus, Skeeter, Jade Champion, and Natty Dread. The Natty Dread scenarios were not immediately available, and had to be unlocked by playing the other characters first.
Multiplayer included the deathmatch mode of the original, as well as the new capture the flag and racing modes with prebuilt maps for each, as well as support for user-made maps. (Nitro multiplayer was not compatible with the Original I'76 or I'76 Gold.)