Here's a few suggestions,
After the cars go out of the screen, make them reappear above the view, maybe even at a random y point out of the screen so the cars won't always be side by side.
Don't let the two oncoming cars overlap.
Turn the car fever off after you use it.
Use both screens, have the oncoming cars start at the top screen and come to the bottom screen.
Make the collisions more accurate, I know it make it easier having a , but it just doesn't look good.
And one last thing: Is there anything that you plan on implementing besides just the communities suggestions? Taking community suggestions is good, but coming up with your own features is better.