D.C. Mun. Regs. tit. 19 § 1204
A sightseeing tour company licensee engaged in the operation of sightseeing tour vehicles in the District shall obtain the necessary approvals of the District Department of Transportation, the District Department of Motor Vehicles, and the Washington Metropolitan Area Transit Commission.
The approval of sightseeing tour vehicles required by § 1204.1 shall be evidenced by the display on each vehicle of the applicable license(s) or certificate(s) issued by the relevant government agencies.
A vehicle operated by a licensed sightseeing tour company shall have at least one (1) licensed sightseeing tour guide on board the vehicle during its sightseeing tours in the District.
Each sightseeing tour company shall ensure that its sightseeing tour vehicles comply with all District parking and traffic regulations.
A sightseeing tour company licensee shall notify the Department within thirty (30) days after any change to the information provided on the application required by § 1202, including a change to the business address or telephone number of the licensee.
The Director may, in connection with the consideration of a sightseeing tour company license application and from time to time during the license term, during regular business hours, require an applicant or licensee to make available to the Director, or the Director's agent, such information as the Director considers necessary to determine or verify whether the applicant or licensee has or retains the qualifications necessary for obtaining or retaining a license, or has violated or failed to comply with an applicable statute or regulation.
Failure to make information available to the Director, failure to furnish to the Director information the Director is authorized to request by this chapter, or failure to furnish to the Director or to permit the Director to make copies of such records maintained by the applicant or licensee as the Director may specify, shall be grounds for denial, suspension, or revocation of a license.
D.C. Mun. Regs. Tit. 19, § 1204