Kill switch master disconnect cut off ???

Most other auto racing sanctioning bodies and I think, all aircraft, are wired to kill the ground, or negative side of the system. I can't say for sure but I assume that NHRA is sticking with the OLD way of doing things, to avoid confrontation with the racers.
Switching the negative side stands less chance of causing arcing(read;fire), the same as taking the negative off your batteries, first.