Wisconsin has several Native American tribal reservations that have major highways running through them. Reservations are sovereign territory; they are not subject to the laws of the State of Wisconsin…sort of. The relationship between the tribes and Wisconsin is long, complicated, and painful. Generally and historically speaking, the tribes have full control over tribal members on tribal lands. They do not, however, have control over non-members on tribal lands. In other words, non-members do not have to follow tribal laws and are not subject to the actions of tribal law enforcement.
Here’s where this gets complicated. A recent SCOTUS decision states that tribal police may detain non-members suspected of violating state or federal law. Historically speaking, though, tribal police are not allowed to detain non-members suspected of violating tribal law.