I was in the Rožnov pod Radhoštěm to see how fast are the best autonomous slot cars in Czech and Slovak Republic. I've made some videos so you can see how the cars are speeding up on the straights and braking before corners. It's simple idea to speed up in on the straight but very hard to implement. Sometimes your learning algorithm is "lost" and has to be synchronized by start lane or on the track crossings. The car is acting much different that you were thinking and the only way to figure out what is wrong is to store some telemetry during the ride to the SD card.
My car was almost excellent on short tracks but on bigger track with lot of corners was behaving unpredictably. One change in the code affected another two parameters and the perfect tuning of the PID, learning algoritm, track synchronization, accelerometer/gyro filtering was very hard.
FYI: I was just the visitor, not the racer in the finals. Because I ended in school round somewhere near the end of the table of winners ;)
The entire playlist of my FRC 2011 videos
The winners' ride: