Wis. Stat. § 344.35: This chapter not to affect other policies.

(1) This chapter does not apply to or affect policies of automobile insurance against liability which may now or hereafter be required by any other law of this state. If such policies contain an agreement or are endorsed to conform to the requirements of this chapter, they may be certified as proof of financial responsibility under this chapter.

(2) This chapter does not apply to or affect policies insuring solely the insured named in the policy against liability resulting from the maintenance or use by persons in the insured’s employ or on the insured’s behalf of motor vehicles not owned by the insured.