I played it on Microsoft Edge. The choppy movement felt less like a performance problem and more like a consequence of how the bus movement was implemented. Like, the overall framerate felt fine, but the bus was teleporting forward. If that's not happening on your end though, then I have no idea.
I just relaunched the game to check and the movement was suddenly fine. So now I'm even more confused. I guess it's just a random chance? Even so, it didn't affect the controls at all so don't worry about it too much.