Please take a look on my server: Fusion. I already scripted a car class that works (but at the moment only with 4 directions - 8 directions and more shouldn't be a problem) with fluent movement. Example cars are on the overworld.
Also multiple players can go by one and the same car (but the first player that enters/or the owner - if set - is the driver).
At the moment I try to rotate a (single direction) car image by setting its angle Clientside so that it isn't rotating jerkily anymore. The rest like movement and triggering an event to the specific car - e.g. if a direction key and/or acelerate/decelerate-key was pressed by the driver - is serverside (for security reasons).