I wish I had a tutorial on the skitching mechanic -- it always felt random when I managed to pull it off.
I didn't hear any sounds when I played, which may have been a bug on my computer's part. In any case, I wish I had gotten to hear that characteristic sound of the board, and the rush of wind.
If you want to give the coins some endogenous value, I would make them sustain the player's current speed. Gives a bit more incentive to go out of your way to collect them. Likewise, make hitting cars anywhere but the "sweet spot" cause the player to slow down. That way you get some nice risk-reward going on.
You can even introduce more constraints to make the game more variable: have closed lanes, traffic accidents, cops to avoid -- you have a very strong foundation to build from here.
Over all, great work! Keep it up!