The 23-year-old cricketer, who was electrocuted by a live rail on the London Underground District Line before getting hit by a train, had high levels of alcohol, cocaine and ecstasy in his system at the time of his death, an inquest heard on Tuesday.
It has also been revealed that a hair sample indicated that Maynard had been a regular user of cocaine for three months before his passing.
"If you had [drug testing] on a regular basis, there would be a starting point of potentially wiping it out completely," Vaughan told BBC Sport.
"Where cricket has to be a little bit wary is if you're just a county player, the season finishes in September and then you're not playing a competitive game until April. We have to be wary that long periods of non-competitive action can lead to boredom.
"It's a long time not to be competing and it's a long time not to be tested. I do think out-of-season and out-of-competition drug testing would be a step forward."
Maynard was stopped by police on suspicion of drink-driving before his death later that night in June last year.