Va. Code § 15.2-3530
When a county and city consolidate into a city, or a combination of counties and a city or cities consolidate into a city, or when any county and all of the incorporated towns located entirely therein are consolidated into a city or cities, the Commissioner of Highways shall continue the full services of the Department of Transportation in those areas which were formerly a county or counties in the same manner and to the same extent such services were rendered prior to such consolidation. Funds for the maintenance, construction and reconstruction of streets within the areas formerly a county or counties shall continue to be allocated as if such areas were still in the county or counties, and such city or cities shall not receive funds for maintenance, construction or reconstruction of streets in those areas. In those areas where the Department of Transportation provides the above services, the governing body of such city or cities, as the case may be, shall have control over the streets and highways to the same extent as was formerly vested in the governing body of the county or counties.
Notwithstanding the above, at any time subsequent to the consolidation, when in the opinion of the Commissioner, the consolidated area which was formerly a county or counties or any portion thereof becomes substantially urbanized, the Commissioner may by agreement with the governing body of the city, transfer the streets in any area deemed urbanized to the city for construction, reconstruction and maintenance, and thereafter funds for such streets shall be allocated as otherwise provided by law for city streets.
Va. Code § 15.2-3530