Even though Matt McQuiddy hadn’t taken a drink or had a smoke in 24 hours, he got a little nervous when a Red Bank police officer asked him to step out of his car during a late-night traffic stop in April 2013.

McQuiddy had just driven under a bridge on Signal Mountain Road — the lanes shifted and he had to swerve to stay in the lines — when Officer Mark Kaylor pulled behind him and flipped on his blue lights. McQuiddy stopped at a gas station across from the entrance to Baylor School around 1:30 a.m.