OK, so two things.
Regarding the angle of motion to start - if your bullet speed is 0, it does not have an angle of motion, and then it defaults to -180 for some reason (left). If you set the speed by default to some small number like 0.1, it will be able to set the motion properly to 270 (up), but also immediately go back to 0 speed due to event 2. Then when you start moving again the correct angle of motion is already set.
Second regarding the rotation speed, perhaps your original device was running at 30 fps to follow the road with /200, so the correct dt value would actually be /(dt*6000) instead. On both my computer (60fps) and phone (90fps) it now follows the road.
However do note that this method of turning in general is subject to minor imprecision due to rounding errors and fps variations. You won't get the same exact result every time, but it should be enough to follow the road.
dropbox.com/s/ngdd3lb57x8mgg2/CarTurning-updated.c3p