The GrandPrix Race Manager V13.0 software has a few different ways of configuring the races. One method is to simply have a car start in lane 1, then 2, etc., until it has raced in all lanes (lane rotation). Another configuration (Perfect-N) does a better job of randomizing when a car races in one lane — which randomizes which cars are racing in any single heat — and appears to be the schedule typically used by the NPWDRL.
I noticed in the Street Rod finals for April (I believe), that the races were simply a lane rotation — the cars had the same cars beside them throughout. In SR, the cars really are sensitive to the cars around them, and really need better randomization as to their lane buddies for each run to give a truer representation of who is fastest.