Wis. Stat. § 345.22
A person may be arrested without a warrant for the violation of a traffic regulation if the traffic officer has reasonable grounds to believe that the person is violating or has violated a traffic regulation.
Wis. Stat. § 345.22
Although this section and s. 968.24 pertain only to crimes and violations of traffic regulations, neither statute forecloses traffic stops to enforce non-traffic civil forfeiture offenses. State v. Iverson, 2015 WI 101, 365 Wis. 2d 302, 871 N.W.2d 661, 14-0515. The statement in Popke, 2009 WI 37, that "a police officer may . . . conduct a traffic stop when, under the totality of the circumstances, he or she has grounds to reasonably suspect that a crime or traffic violation has been or will be committed," did not purport to circumscribe the universe of possible scenarios within which traffic stops permissibly may occur, or to make such limits contingent on whether the legislature has titled a particular law a "traffic regulation." A reasonable suspicion that a violation of the littering statute, s. 287.81, a non-traffic civil forfeiture offense, had occurred justified a brief and limited traffic stop. The more onerous standard of probable cause would also therefore justify a traffic stop. State v. Iverson, 2015 WI 101, 365 Wis. 2d 302, 871 N.W.2d 661, 14-0515. A city police officer is a traffic officer within s. 345.22. 61 Atty. Gen. 419.