There were 3 expansion products for Interstate ’76, all released at the same time, with a fair amount of confusion to them. From the people I talk to, these are the ones that most people seem to have played. I was the lead, and only, programmer on these products, so I know that all three were basically the same codebase with minor changes.

Oddly enough I believe these expansions of I’76 were more popular than the later full I’82 game, even though that product was developed by an entirely separate and full team of like 20 people, whereas our product was 1 programmer, 1 external contract programmer, 2 producers, 3 designers, and an artist. There were occasionally a few more artists, but I think we were the smallest team at Activision at the time.

I’76 Nitro Pack - New levels, new network games, custom car decals, Direct 3D support, Glide, Rendition, and force feedback were added to the original game. This package expanded the original game installation for previous owners.

I’76 Nitro Riders - This version is a stand alone version of the Nitro Pack that allows you to play all the new levels without owning the original game.

I’76 Arsenal - This was a full combination of the original title, upgraded + the Nitro Pack Expansion.