Thanks for the suggestions
I inserted a new screen to select the difficulty (car speed).
I made constraint "harder" so car loose less speed in case of contacts
I reduced, the size of the info text to contains only the 2 used lines.
It is also possible to terminate practice when desiderate.
2 new keyboard buttons are used to accelerate and break.
Clean up meshes is a difficult task, since it is partially generated by the application... I will do in the near future.
 "Tail Arena"){kind=icon}
 "Traffic 2"){kind=icon}