A governmental unit may be held liable for damages in an action to recover for bodily injury, personal injury or property damage caused by its fault or by fault attributable to it, arising out of ownership, occupation, maintenance or operation of all motor vehicles, and all premises; provided, however, that the liability of any governmental unit with respect to its sidewalks, streets, and highways shall be limited as provided in N.H. Rev. Stat. Chapter 231 and the liability of any governmental unit with respect to publicly owned airport runways and taxiways shall be limited as set forth in RSA 422.