This seems like great chaotic fun! The "skirmishers" are an interesting addition that really establish this as a true wargame / racing hybrid.
It's hard to comment on the balance as I haven't played it but I don't see anything particularly problematic. Even if it turned out to be janky it would only add to the theme of the game!
I disagree with others that there is too much going on. The core idea is apocalyptic racing and I think this design suits that very well without becoming too complex. There are some small typos in the document but nothing that obfuscates the intended meaning, and the game seems like it would play quite fast once one has a rhythm going.
My only real suggestion would be to have printable sheets that allows players to track their chosen vehicle, skirmishers, armor/health, and upgrades.
Nice work!