Any HSV with a GVWR of more than 10,000 pounds or a vehicle with the aisle through the center of the unit shall have a minimum clearance of 12 inches leading to the emergency door when measured at any point between the seats or between any seat and emergency door frame in the case of a vehicle with a side emergency door. An open area for wheelchairs may not be considered an aisle.
Wis. Admin. Code Department of Transportation Trans 301.10
For purposes of measurement, the 12-inch aisle clearance is required when measured from a foldaway seat when the seat is in its fully deployed and open position. For purposes of measurement, the 12-inch aisle clearance is required from a flip-up seat that complies with s. Trans 301.29(3) at a side emergency door location when the seat is not occupied and is in its automatically closed position.