D.C. Mun. Regs. tit. 18, r. 18-2201
Upon all roadways of sufficient width, a vehicle shall be driven upon the right half of the roadway, except as follows:
Upon all roadways, any vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall be driven in the right-hand plane then available for traffic, or as close as practicable to the right-hand curb or edge of the roadway, except when overtaking and passing another vehicle proceeding in the same direction or when preparing for a left turn at an intersection or into a private road, driveway, or alley.
Drivers of vehicles proceeding in opposite directions shall pass each other to the right, and upon roadways having width for not more than one lane of traffic in each direction, each driver shall give to the other at least one-half of the main traveled portion of the roadway, as nearly as possible.
Upon a roadway so designated for one-way traffic, a vehicle shall be driven only in the direction designated at all or such times as shall be indicated by official traffic control devices.
A vehicle passing around a rotary traffic island shall be driven only to the right of the island: Provided, that this subsection shall not apply to apparatus engaged in snow removal and control.
Whenever any roadway has been divided into two (2) or more clearly marked lanes for traffic, the following rules, in addition to all other rules consistent with this subtitle shall apply:
Whenever any highway has been divided into two (2) or more roadways by leaving an intervening space or by a physical barrier or clearly indicated dividing section so constructed as to impede vehicular traffic, every vehicle shall be driven only upon the right-hand roadway, unless directed or permitted to use another roadway by official traffic control devices or police officer.
No vehicle shall be driven over, across or within any dividing space, barrier or section, except through an opening in the physical barrier or dividing section or space or at a crossover or intersection or an unraised, paved dividing section with pavement markings only, unless otherwise directed by official traffic control devices.
The driver of a vehicle shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of the vehicles and the traffic upon and the condition of the roadway.
The driver of any motor vehicle drawing another vehicle when traveling upon a roadway which is following another motor vehicle drawing another vehicle shall, whenever conditions permit, leave sufficient space so that an overtaking vehicle may enter and occupy the space in front of the drawing vehicle without danger, except that this shall not prevent a truck or motor vehicle drawing another vehicle from overtaking and passing any like vehicle or other vehicle.
No driver shall enter an intersection or marked crosswalk, unless the movement can be made such that the vehicle can completely clear the intersection without obstructing the passage of other vehicles or pedestrians, notwithstanding any official traffic control device indication to proceed. A vehicle shall not enter an intersection to turn right or left unless there is sufficient space on the roadway being entered to accommodate the vehicle.
No person shall drive a vehicle onto or from any controlled access roadway except at such entrances and exits as are established by the Director.
The Director may regulate or prohibit the use of any controlled-access roadway or highway by any class or kind of traffic which is found to be incompatible with the normal and safe movement of traffic.
The Director shall erect and maintain official traffic control devices on the controlled access highway on which such prohibitions are applicable and, when in place, no person shall disobey restrictions on such devices.
D.C. Mun. Regs. tit. 18, r. 18-2201