Vanilla – Roller Coaster with Binary Lap counter and automatic track switcher!

I use a sticky piston driven bit counter as a means to increment from 0 every time a detector rail is driven over. This configuration allows me to limit the number of laps to 4 at which a side rail is activated parking the cart and resetting the counter and track for a fresh start.

Skip the lap test to 6:15 via http://www.youtube.com/watch?v=gqlrKIjx7I8#t=6m15.6s

Videos that helped in this design:

The smallest binary counter in minecraft!
http://www.youtube.com/watch?v=Z4S1e-LICFM

Minecraft Logic Gates
http://www.youtube.com/watch?v=P7E4K5D834g