DUI CHECKPOINTS NEUTRAL MATHEMATICAL FORMULA
A related concern is that motorist should not be subject to the unbridled discretion of the officer in the field as to who is to be stopped. Instead, a neutral formula such as every driver or every third, fifth or tenth driver, should be employed. To permit an officer to determine to stop any particular driver or car when there is no legitimate basis for the determination would be to sanction the kind of unconstrained and standardless discretion which the United State Supreme Court sought to circumcise in its decision in Prouse, [citations omitted]. In all the checkpoint programs at issue here, neutral mathematical selection criteria were used.
Id., at 1342 (emphasis added)