D.C. Mun. Regs. tit. 18, r. 18-750
When any motor vehicle was originally equipped with an emission control system, that system shall be maintained in good working order, and no person shall disconnect any part of that system, except temporarily in order to make repairs, replacements, or adjustments, and no person shall modify or alter that system in its operation.
No person shall operate, and no owner shall cause or permit to be operated, any motor vehicle originally equipped with a pollution control system while any part of that system is disconnected or while that system or its operation is modified or altered.
The engine, power, and exhaust mechanism of each motor vehicle shall be equipped, adjusted, and operated to prevent the escape from the vehicle of a trail of visible fumes or smoke for more than ten (10) consecutive seconds.
Each gasoline-propelled motor vehicle of the 1968 model year or any model year thereafter, when operated on a street or highway, shall be equipped with a positive crankcase ventilation valve which shall be in good operating condition.
No person shall operate a gasoline-propelled motor vehicle of the 1968 model year or any model year thereafter without the vehicle being equipped with a positive crankcase ventilation valve which shall be in good operating condition.
D.C. Mun. Regs. tit. 18, r. 18-750