Welcome!
You can do Maps by your own in MS Paint,Gimp,etc...

(Walls and obstacles needs to be the color white!(or change it in the newcar.py)
//BORDER_COLOR = (255, 255, 255, 255) # Color To Crash on Hit // line 19

For selfmade Tracks dont forget the Starting Position 
(self.position = [830, 920] # Starting Position by default) // line 32

To change map just insert your own PNG file in newcar.py // line 177
game_map = pygame.image.load('yourMapHere.png').convert()

You can do your own settings in the config file

Have fun
Reggaetuna