OP can report back on what the bar was, but I doubt people were getting rejected simply for being aloof or untalkative. And it's unfair in the opposite direction to try to apply the "Magical Negro" trope to anyone with a blue-collar job. By that bar -- it would be better to completely ignore the driver and treat them as a nonentity, which we (hopefully) know is wrong.
Use whatever resources are at your disposal to vet candidates.