Va. Code § 33.2-1900
The development of transportation systems, composed of transit facilities, public highways, and other modes of transport, is necessary for the orderly growth and development of the urban areas of the Commonwealth; for the safety, comfort, and convenience of its citizens; and for the economical utilization of public funds. The provision of the necessary facilities and services cannot be achieved by the unilateral action of the counties and cities, and the attainment thereof requires planning and action on a regional basis, conducted cooperatively and on a continuing basis, between representatives of the affected political subdivisions and the Commonwealth Transportation Board. In those urban areas of the Commonwealth that together form a single metropolitan area, solutions must be jointly sought with the affected political subdivisions and highway departments. Such joint action should be conducted in a manner that preserves, to the extent the necessity for joint action permits, local autonomy over patterns of growth and development of each participating political subdivision or locality. The requisite joint action may best be achieved through the device of a transportation district, having the powers, functions, and duties set forth in this chapter. In the provision of improved or expanded transit facilities, it is the policy of the Commonwealth to make use of private enterprise to the extent reasonably practicable.
Va. Code § 33.2-1900