I used scripts from this project for controlling the car and it was fairly easy to implement reverse to the car script (vehicle.gd) however it is not working really flawlessly. I can imagine it would work much better if I could get some speed value of the car to decide if the car is moving or not, then I could with same key control if car should brake when moving (increase brake value) or if it's not moving to reverse (increase negative engine force value). Does anybody try to do this before? Is there any reasonable way to know if the car is moving and/or in what speed is car moving?
https://github.com/godotengine/godot-demo-projects/tree/master/3d/truck_town