Interstate '76 is an autocombat game set in an alternate history version of 1976.
In the single-player T.R.I.P. ("Total Recreational Interactive Production") mode, players take on the role of an auto-vigilante named Groove Champion (AKA "Swinger"), who with the help of his partner Taurus (AKA "Stampede") and their mechanic Skeeter are investigating the murder of Groove's sister, Jade (AKA "Vixen"). The missions entail a variety of different goals, including seek & destroy combat, escort duties, racing, and even point-to-point travel. The primary enemies encountered are "Creepers" (enemy auto-vigilantes), but some missions also include fixed turrets, police vehicles, helicopters, and even a few military tanks. At the end of most missions, the player can salvage parts from wrecked vehicles and use them to upgrade their own vehicle with a variety of different weapons.
Other play modes include "Auto Melee", a simple deathmatch mode against AI-controlled vehicles, and multiplayer. Online multiplayer games could support up to 8 players at once, and took place on the same maps/levels available for the Auto Melee mode or on countless user-made maps. Multiplayer games were primarily the deathmatch style, but team play and racing were not uncommon.
Almost all of the vehicles in the game were based on real vehicles from the 1970's (and older), although all of the names were changed for licensing reasons. For example, the "Picard Piranha" used for the majority of the T.R.I.P. missions was directly based on the Plymouth Barracuda.