D.C. Mun. Regs. tit. 18, § 434
434.1 Trip permits for apportionable vehicles, as defined in section 2 of the International Registration Plan Agreement Act of 1997, effective September 5, 1997 (D.C. Law 12-14; D.C. Official Code § 50-1507.01), shall be valid for a six (6) day period, to begin on a day determined by the Director.
SOURCE: Final Rulemaking published at 53 DCR 847 (February 10, 2006).