In a 1995 unpublished Wisconsin case, a man was living with his brother for a short time. The man, had two vehicles which he had insurance for. However, for some reason, he was driving his brother's vehicle and not his own when he collided with a bicyclist.
His insurance company, American Family, denied coverage and claimed that the "drive other car" provision applied. That provision held, "that no coverage would extend for:
[b]odily injury or property damage arising out of the use of any vehicle, other than your insured car, which is owned by or furnished or available for regular use by you or any resident of your household.
The court went on to determine that although the driver was living with his brother (the person whose car was involved in the accident), they were not members of the same household because his brother had only moved back home temporarily and had a certain date to move out for his wedding, and early termination was highly probable.
The court also went on to find that the driver did not have "regular use" of the vehicle because he only used it on sporadic occassions and no regular use was actually made of the car.
The result meant that the exclusion did not apply and the driver's insurance would be applied to the collision with the bicyclist.