It is not just USA.......the whole WORLD are basicly using AMB as a master (main) lap counter.........then software like Jlap for the best combination.
Couple years aga I was racing at the track using the analog KoPropo lap counter....yes, it is cheaper, but I would say 7 out of 10 times that thing does not work properly, on top of that, it use limited transponder (using AM or FM crystal) so...only certain # of cars can run at 1 time....and you cannot get your own transponder, you have to share with others.
Software support of that system is horrible, I believe only DOS program is able to run with the KO........who is using DOS now?
Overall, spend the $5000 now for the AMB (come with 10 rechargable transponder) and $300 for software like Alycatt (very good and easy to use program that is capable to run ROAR national race for 100 plus racers easily) for now....when you are done, sell it, its resale value is still very high even though it is used.......(you can tell from a used personal transponder from AMB is good $70 plus, when new is $90)....
SPEED PASSION - King Golden, Speed Passion USA, Speed Power, Hirosaka Pro Products, East Coast Bodies, Schumacher Racing, Hurricane Motorsports, Serpent America, Sweep Racing USA. http://www.spautomobile.com/en/index.asp (SPEED PASSION AUTOMOTIVE)
NEW Speed Power/Speed Passion direct sale site - http://shop.speedpowerrc.com/