In Simmons v. Commonwealth, 238 Va. 200, 380 S.E.2d 656 (1989), the Virginia Supreme Court considered a license and registration checkpoint established and conducted by two state troopers on their own initiative. The troopers stopped and inspected every vehicle passing through the checkpoint. Holding the checkpoint to be constitutionally impermissible, the Court said: We do not read Prouse to stand for the proposition that stopping all traffic at a roadblock constitutes sufficient restraint on the exercise of discretion by police officers to transform the stop into a constitutionally valid roadblock. While this approach may eliminate the constitutional vice inherent in a random spot check or stop and therefore be a preferred practice, . . . the roadblock also must be undertaken pursuant to an explicit plan or practice which uses neutral criteria and limits the discretion of the officers conducting the roadblock. The evidence in this case establishes that the decision to establish the roadblock as well as its location and duration was solely within the discretion of the troopers. No advance approval or authorization from any supervisor or superior officer was required to set up the roadblock. 238 Va. at 203-04, 380 S.E.2d at 658-59.