There are four play modes available in the game: the "T.R.I.P." (an acronym for "Total Recreational Interactive Production"), which follows the game's protagonists in an episodic story; "Multi Melee", an on-line deathmatch version of the game; "Auto Melee", a deathmatch with computer-driven cars; and "Scenarios", short free-standing adventures featuring the game's protagonists. The primary difference between the scenarios and the T.R.I.P., length of play aside, is that the player has a much broader choice of vehicles in the scenario mode, while the player is limited to only one car during most of the T.R.I.P. mode. The game's vehicles are faithful reproductions of various cars and trucks from the era, both in appearance and driving characteristics, though the names have been changed.
The game is based on the engine used for Activision's MechWarrior 2: 31st Century Combat, and requires a fair amount of strategy through the course of the game, as the player must balance the vehicle's armor and weapon load-outs appropriately in order to successfully complete the various missions. In the game's story mode, the player must also manage and repair equipment salvaged from the wrecks of opponents.
The game is set in the south-western United States of America in an alternative version of the year 1976, during a prolonged oil crisis. All the in-game vehicles in Interstate '76 are based on actual automobiles, including many period American muscle cars.
Whilst set in an alternative timeline, in which the 1973 oil crisis is still ongoing, the game progresses through real towns and locations in the south-western United States including Lubbock, Seagraves, Seminole and Pecos in Texas and Roswell and Carlsbad in New Mexico. The game's final showdown takes place at Fort Davis, Texas, although the real Fort Davis National Historic Site, a surviving Indian Wars' military post, bears little resemblance to the high-walled compound depicted in the game.
The game focuses on the daring exploits of Groove Champion, his partner Taurus, and their mechanic, Skeeter. A powerful but shadowy figure is recruiting autovillains (also known as "creepers") from around the country for a private army. Groove's sister, Jade, and Taurus are investigating the movements of the army when, on the night of July 3, 1976, Jade Champion is murdered outside Lubbock, Texas. Taurus recruits a reluctant Groove to the cause, with Groove operating Jade's heavily armed Picard Piranha. The game follows Groove and Taurus' quest for revenge and the truth.
Taurus serves as mentor and partner to Groove in the first few missions, until he is seriously wounded in an ambush. His own car ("Eloise") is destroyed and he spends the rest of the T.R.I.P. riding along in the team's van with Skeeter. This allows Groove, the player's character, to take center stage.
The trail leads to Antonio Malochio, a smuggler with a questionable past. Malochio has purchased a hydrogen bomb on the black market and plans to use it to destroy the West Texas Federal Stock - the largest oil reserve in North America. If he succeeds, the gas crisis would become a gas panic, leading to anarchy, during which time Malochio and his army of auto-villains (secretly backed by OPEC) would seize power.
In the course of the T.R.I.P., Groove's driving and shooting skills are put to the test against members of Malochio's organization (some of whom, like Cloaker and Disco Cat, are quite colorful for minor characters); the creeper Patriot and his cronies, former foes of Jade's who may actually be ghosts; a corrupt county sheriff and his deputies (the "fuzz") who've been paid off by Malochio; and even the Jeep-driving operators of a mysterious desert testing range.
Groove and company finally arrive at Fort Davis, Malochio's hideout, just as he has armed the bomb and is preparing to leave; however, Groove taunts Malochio into one last duel. When the player wins, Groove kills Malochio and disarms the bomb, saving the oil supply and completing the game.
Because of the limitations of the game's engine, the characters are only seen in prerendered cutscenes, and then as figures constructed of colored but untextured ("flat") polygons. This simple design was chosen to make them easy to animate and to fit in with the overall look of the game. Part of Interstate '76's introduction takes the form of opening credits for a television action series; in this cutscene, each of the characters is credited to a fictional actor.
- Groove Champion (played by "Everett Mann", voiced by Andrew Heckler) - The protagonist of Interstate '76 and middle Champion child, Groove reluctantly accepts the responsibility of the auto-vigilante lifestyle, takes the CB handle of "Swinger" and drives with Taurus to fight against Malochio's goons. He inherits his sister's 1971 Picard Piranha at the start of the game.
- Taurus ("James W. Styles", voiced by Greg Eagles) - Taurus isn't his real name- it's what people call him. He lived as a poet in New England with a wife and daughter, who were killed by criminals. He helps Groove to adjust to being a vigilante, guiding him along his quest. His poetry could be sampled by pressing the 'C' key while in driving mode. He goes by the handle "Stampede" and drives a 1966 Jefferson Sovereign he has named "Eloise".
- Jade Champion ("Katherine Knolls", voiced by Lisa Picotte) - For many years, Jade lived a secret life as an Auto-Vigilante. The rest of her family never knew a thing, presumably because Jade wanted to protect them from her enemies. The game begins with Groove taking up her cause, symbolized by his inheritance of her car. Her handle was "Vixen."
- Skeeter ("Willard Dicot III", voiced by Tom Kane) - Skeeter serves as the mechanic and Greek chorus for the series' heroes. He repairs the player's vehicles between missions and occasionally is the focus of the in-game missions. He goes by the handle "Monkey Wrench." He drives a 1971 Street Van which acts as the team's support vehicle.
- Antonio Malochio ("Carlo DeFungi", voiced by John de Lancie) - The primary villain of Interstate '76, a shady businessman with a history in Vietnam and Cambodia. Originally believed to be using the handle of "Cloaker", it is revealed that his codename is in fact "Giotto" and that "Cloaker" is merely one of his lieutenants. He drives a 1969 Courcheval Manta.
The Interstate '76 soundtrack was composed by Arion Salazar who would later achieve fame as a founding member of Third Eye Blind. The music was performed under the name "Bullmark" with Salazar on bass, Santana-alumni Tom Coster on keyboards, and Bryan Mantia, who among his performing credits previously played with Primus and Guns N' Roses, on drums. Eric Valentine (who also mixed for Third Eye Blind at the time) mixed and engineered for the soundtrack. The soundtrack recreated the funk sound of '70s' film and television theme music. Some are sly variations of popular '70s' funk tracks, such as "Never Get Outta The Car"'s pastiche of The Brothers Johnson's 1976 hit "Get The Funk Out Ma Face". The soundtrack was recorded using vintage instruments and recording technology in order to as closely reproduce this sound as possible. Activision released a separate official soundtrack CD which contained all tracks from the game and unreleased tracks from the recording sessions. Versions of the background music tracks can also be found on the game play disc as redbook audio.
Interstate '76 spawned a prequel/stand alone expansion pack, Nitro Pack (known as Nitro Riders in some territories) and a direct sequel, Interstate '82, as well as spin off the Vigilante 8 series for home video game consoles. A graphically enhanced version of the original game, Interstate '76: Gold Edition, was also released. The Gold Edition was later bundled with the Nitro Pack expansion as Interstate '76 Arsenal. On Feb 18, 2010 Good Old Games released a version of Interstate '76 and Arsenal in a bundle playable on modern operating systems and hardware.
The film rights to the game were acquired in March 1998 by 20th Century Fox and Davis Entertainment with Todd Smith and Danny Simonds producing. There have been no reports since then and as of 2010 the project has likely been consigned to development hell.