Wis. Stat. § 346.19: What to do on approach of emergency vehicle.

(1) Upon the approach of any authorized emergency vehicle giving audible signal by siren the operator of a vehicle shall yield the right-of-way and shall immediately drive such vehicle to a position as near as possible and parallel to the right curb or the right-hand edge of the shoulder of the roadway, clear of any intersection and, unless otherwise directed by a traffic officer, shall stop and remain standing in such position until the authorized emergency vehicle has passed.

(2) This section does not relieve the operator of an authorized emergency vehicle from the duty to drive with due regard under the circumstances for the safety of all persons using the highway.