When acquiring land for the construction of highways with divided roadways, the Commissioner of Highways may, if he deems it necessary and appropriate, also acquire by gift, purchase, or by the exercise of the power of eminent domain as vested in him by § 33.2-1001, in addition to the land necessary for such highways, sufficient land in the median for use for public mass transit and may convey or otherwise make available the same to a public agency or authority or public service corporation or public service company for the construction and operation thereon of public facilities for mass transit. Such additional land shall be acquired only after an agreement has been made between the Commissioner of Highways and a public agency or authority or public service corporation or public service company whereby such agency, authority, corporation, or company has agreed to pay the cost of the additional land acquired and all expense incidental to its acquisition. The condemnation of such land to be conveyed for use for public mass transit shall be governed by the procedure prescribed by this article and may be carried out at the same time if against the same property owner and if against the same landowner or in the same proceedings in which land is condemned for highway purposes. The Commissioner of Highways may, under the same procedure and conditions prescribed by this article with respect to property needed for highway purposes, enter upon and take possession of such property to be conveyed to a public agency or authority or public service corporation or public service company in the manner provided in §§ 33.2-1018 through 33.2-1027. The Board is authorized and directed with the consent of the Federal Highway Administration to permit the Washington Metropolitan Area Transit Authority to commence construction of rapid transit and ancillary facilities within the proposed median of Interstate 66 between Glebe Road in Arlington County and Nutley Road in Fairfax County, provided that (i) construction of rapid transit shall conform with highway plans and that construction procedures shall be reviewed and approved by the Commissioner of Highways and (ii) prior to construction of rapid transit, a mutually satisfactory allocation of cost shall be agreed to by the Washington Metropolitan Area Transit Authority, the Board, and the Federal Highway Administration.