All motor vehicles owned or leased by a statutory or home rule charter city, county, town, school district, metropolitan or regional agency, or other political subdivision, except for unmarked vehicles used in general police and fire work, arson investigations, Department of Human Services investigations conducted by central office staff, and county fraud prevention investigations conducted by county or contract fraud prevention investigators, shall have the name of the political subdivision plainly displayed on both sides of the vehicle in letters not less than 2-1/2 inches high and one-half inch wide. The identification must be in a color that contrasts with the color of the part of the vehicle on which it is placed and must remain on and be clean and visible throughout the period of which the vehicle is owned or leased by the political subdivision. The identification must not be on a removable plate or placard except on leased vehicles but the plate or placard must not be removed from a leased vehicle at any time during the term of the lease.