D.C. Code § 10-105: Power to make and enforce vehicle and traffic regulations.

The Director of the National Park Service is authorized and empowered to make and enforce all regulations for the control of vehicles and traffic, and limiting the speed thereof on roads, highways, and bridges within the public grounds in the District of Columbia, under his control, subject to the penalties prescribed in the Act entitled “An Act regulating the speed of automobiles in the District of Columbia, and for other purposes,” approved June 29, 1906.