D.C. Mun. Regs. tit. 11-I, § 568
568.1 The purposes of the D-7 zone are to permit high-density commercial development and, in conjunction with sub-area objectives and regulations, to reinforce Pennsylvania Avenue's unique role as a physical and symbolic link between the White House and the U.S. Capitol.
SOURCE: Final Rulemaking published at 63 DCR 2447, 3041 (March 4, 2016 – Part 2).