Why is Vehicle::updatePos called on the client?

#1 i'm not familiar with the vehicle code, but if it's similar to the player code, i can give a broad overview:

for a given object, the server calculates physics about 32 times per second. (or maybe 10; i'm not sure). so the client gets updates from the server at most that frequently. however the client framerate is likely quite a bit higher, so the client ticks its copy of the simulation each frame. when the next update from the server comes along, the client makes any corrections between its own simulation and what the server is sending.

#2 It's called once per tick on both the server and the client from the processTick function, so I think for this function in particular that's quite right.