All hear this Devs of the BeamNG game. I'd like you to take the time and read this. Multiplayer would be very nice. Like add some vehicles, and change up the UI for multiplayer mode. And the modes for multiplayer can be like. "Police Chase" - "Races" - "Free roam" - "Derby". Like something like that. And would be awesome if there was a story mode too. But I think you guys kinda already have that.
online multiplayer is near impossible considering the amount of data that would have to be transmitted since the physics are calculated on the fly. splitscreen would be possible but is not first priority right now.