Ok.... I'm stopping the ranting here about using the search bar to make a simple response. As of right now, the physics cause too heavy of a load to make server based gameplay possible, unless you have an insane computer and an even more insane Internet speed. Then whoever was running the server would have to have an EVEN MORE insane machine to run the server. Until optimization is maximized and CPU load is minimized, I wouldn't get my hopes up. Most people can't spawn more than 2 cars (standing still) without FPS dropping through the floor (you can't make delicious bagels and play games with the same machine). So, it wouldn't be practical, or even feasible to have 10 vehicles from different players running into each other, unless someone found a way to ship all the calculations to a central hub, and them ship the results back to keep lag at a minimum, provided you have an awesome Internet connection/speed. Long story short... The game runs WAY to hard on most hardware to make it possible to run multiplayer.