Line follower racing is quite popular at Robogames in the US and some of the machine there are very sophisticted with line tracking heads that are on a servo so they can follow the line at high speed and not lose it. I entered it once by mail, with my sister in law runnng the robot for me. My machine finished [and not all of them did] in about 40 seconds; the winner did it in about 4 seconds. I suspect they are faster now. Remind me before the next live event and I'll dig it out and bring it along and we can race.