State v. Swanson
In State v. Swanson, 164 Wis. 2d 437, 475 N.W.2d 148 (1991), the defendant was observed at 2 a.m. driving onto the sidewalk in front of a bar, nearly hitting a pedestrian. Although he smelled of intoxicants, Swanson had no trouble standing and did not have slurred speech.
Before placing Swanson in his squad car to take field sobriety tests, the officer performed a pat-down search and discovered marijuana on him.
Swanson was then arrested, handcuffed and placed in the back of the squad car. See Swanson, 164 Wis. 2d at 442-43.
Swanson, however, does not establish a rule that field sobriety tests are always required in order to have probable cause to arrest for driving while under the influence of intoxicants. The Court suggested that the following indicators are not sufficient to show probable cause to arrest for motor vehicle while under the influence of an intoxicant (OMVWI):
(1) erratic driving;
(2) an odor of intoxicants emanating from a defendant while he speaks;
(3) an incident occurring approximately at the time when bars close in Wisconsin. Swanson, 164 Wis. 2d at 453-54 n.6.
The Court expressly declined to address whether probable cause existed to arrest Swanson for other than possession of a controlled substance, commenting only that the officers "arguably lacked probable cause to arrest Swanson at the time of the search." Id. at 453 n.6.