Relating to authorizing the duly and legally constituted governing bodies of any city, county, town, village, conservation district, drainage district, water district, navigation district, port district, and any and all other political subdivisions of the State of Texas to use their funds for the purpose of paying premiums on liability insurance on officers and employees while the officers and employees are operating automobiles, motor trucks, other motor vehicles and any and all other equipment, used by said political subdivision; preventing insurance companies writing such insurance from using the immunities of said political subdivisions from liability in defending against claims for damage caused by the insured, its officers or employees while they are operating automobiles, motor trucks, other motor vehicles and any and all other equipment, used by said political subdivision.