The graphics and music were good, but it would be so much better if the buttons you needed to press were in a straight line. It's fine when the people were going quite slowly but when they sped up you could easily get confused and click the wrong key. Also, since there is no penalty for clicking when there is no person there you can just spam all the buttons and get a high score really easily.
Another thing that I noticed was that I wasn't able to look at the scenery very much because I had to concentrate on the roads most of the time. I don't know what you could do to fix this, but it's still worth pointing out.