Va. Code § 15.2-3307
Notwithstanding any other provision of law, any city that is barred or that may hereafter become barred from further annexation may, by resolution passed by a majority vote of its governing body, elect to be treated the same as an immune county for purposes of state police services and for the maintenance and construction of streets and highways. Such election shall be exercised by notifying the Governor of the election at least two years prior to the beginning of the biennium in which it takes effect. If, after a minimum period of eight years following the date upon which such treatment has become effective, a city wishes to terminate such treatment as an immune county, it shall notify the Governor of its intention to return to being treated as a city for such purposes. Such return shall become effective two years after such notification to the Governor.
Va. Code § 15.2-3307