D.C. Mun. Regs. tit. 18, § 100
100.1 The rules and regulations set forth in this chapter govern matters relating to driver's licenses, learner's permits, provisional permits, and non-resident driving permits, including qualifications for licenses; medical and physical standards for licenses; procedures for application, testing, issuance, and renewal of driver's licenses; duplicate and modified licenses; annotations on licenses, and other matters.
100.2 No person, except those expressly exempted by § 100.3, shall drive any motor vehicle in the District of Columbia unless he or she has a valid license under the provisions of this chapter.
100.3 The following persons are exempt from the license requirements set forth in this chapter:
(a) Non-residents exempt under the provisions of § 8 of the Act of March 3, 1925, as amended (D.C. Code § 40-303 (1986));
(b) High school or junior high school students fifteen (15) years of age or over who are enrolled in an approved driver education and training course, when operating an approved driver education motor vehicle under instruction and accompanied by a licensed motor vehicle driving instructor.
100.4 The Department shall not issue an operator's license to any of the following:
(a) Any person who is under sixteen (16) years of age;
(b) Any person who is an habitual drunkard, or is an habitual user of narcotic drugs, or is an habitual user of any other drug to a degree which renders him or her incapable of safely driving a motor vehicle;
(c) Any person who has previously been adjudged to be afflicted with or suffering from any mental disability or disease and who has not at the time of application been restored to competency by the methods provided by law;
(d) Any person required by this title to take an examination, unless that person has successfully passed the examination; and
(e) Any person, when the Director has good cause to believe that person by reason of physical or mental disability would not be able to operate a motor vehicle with safety.