According to
Here, V8Supercar drivers shall be having an increase in the number of random drug tests they undergo from the current once a year, to three times a year.
Even Mr McKay weighs into the argument
Here
It is a good move to show the world that V8Supercar, and CAMS, does not shirk its responsibility in reasonably ensuring its sport is drug free.
Presumably this testing will make its way into other levels of circuit racing as well some time in the future..