What about laying a really fine coordinate system over ervery map, and just sending tghe changes of the coordinates to the other playrs, that would allow more complexity then just "move right"
I'm pretty sure that's basically how need for speed, forza, etc. do it. the problem is with this game, then you only have information on where the car as a whole is (or maybe the refnodes in the chassis), so if i crashed into another car, there's no data for where the bumper/fenders and other external parts are, so it wouldn't know things like "when" to crash. and if you were to just make each computer guess where the other person's front bumper is, then you have the problem of De-syncing, if one persons framerate is lower, or something is slitghtly off, the cars can crash completely differently on either person's screen. trust them, they've considered and tried every reasonable option, and the way they're doing it is practically the best.
Then, they may need to lower their standarts for Multiplayer, i think, for the most part of the community, its good enough to just cruise around with a friend, without collision. I think, that would be better than nothing. Or im just too optimsitic