Without warning or an error message, I am able to enter vehicles and be a passenger but I am not able to drive vehicles properly on dedicated multiplayer servers regardless of the host. Single player and listen multiplayer work fine. Peers playing in the server can still drive the vehicles though. I've also managed to rule out input devices causing it by trying different keyboards, different mice, and removing the key bindings all together.

https://www.youtube.com/watch?v=jQQ6mzir5MY

I cannot use any vehicles that have wheels. APCs, helicopters, jets, and tanks work fine. It seems to only be in vehicles that use wheels.