Nice little game =) I got almost 4000 points after a few attempts. On the first tries I lost very quickly because we lose on the first mistake. So the game can be somewhat difficult at first, but once you get the hang of it, it's far easier :)
Maybe you could add a number of cars you can miss (like having several "lives") to make it better at first... and have the speed of cars slowly increase to make it harder and harder after a while!
Good job, thx for contributing :)