The stop of Kowalewski’s car was supported by probable cause that she violated § 346.34(1)(b), which requires a drive to use a turn signal “[i]n the event any other traffic may be affected by the movement” of the vehicle.
The officer’s squad car was the only other car on the road (it was 2:30 a.m.), but that constitutes “any other traffic”; and the fact the officer was behind Kowalewski means that her movement from a lane of traffic into a turning lane “may” have affected the officer. (¶¶2-5, 8, 14).
Kowalewski invites the court of appeals to review the squad car video to see for itself that Kowalewski’s movement wouldn’t have affected the officer, but the court declines. It’s not a fact-finder, the circuit court found the officer’s testimony credible, and Kowalewski doesn’t develop an argument that the circuit court’s factual findings were clearly erroneous. It also rejects as a “red herring” the argument that the officer mistakenly believed the law requires drivers to use a signal every time they move. (¶¶15-17).