DC Gives Same-Lane Passing to Bicycles, Not Motorcycles

There is nothing to look up under the words lane splitting or filtering in the District. A full-text search of all 24,113 sections of the D.C. Official Code and of every section of Title 18 DCMR returns no provision using those terms, no two-abreast allowance for motorcycles, and no prohibition aimed at them by name. That absence has to be read against what the District did write, because the surrounding rules answer the question anyway.

Start with what a motorcycle is here. The Title 18 definitions describe a motorcycle as a motor vehicle with a seat or saddle for the operator and two or three wheels in contact with the ground, excluding a motor-driven cycle or a motorized bicycle unless operated above thirty miles per hour, and excluding a three-wheeled motor vehicle with a cab and windshield. Because a motorcycle is a motor vehicle, the general lane rules bind it exactly as they bind a car.

Section 2201.6(a) supplies the core duty. Where a roadway is divided into two or more clearly marked lanes, a vehicle shall be driven as nearly as practicable entirely within a single lane and shall not be moved from that lane until the driver has first ascertained that the movement can be made with safety. Riding the white line between two lanes of traffic is not being driven within a single lane. Section 2201.2 adds that a vehicle proceeding at less than the normal speed of traffic must keep to the right-hand lane or as close as practicable to the right curb, which cuts against threading between lanes rather than for it.

Section 2202 then governs the pass itself. Under § 2202.2 a driver overtaking another vehicle proceeding in the same direction shall pass to the left of it at a safe distance and shall not return to the right until safely clear. Passing on the right is permitted only in the three situations listed in § 2202.5: when the overtaken vehicle is making or about to make a left turn, on a street with unobstructed pavement not occupied by parked vehicles and wide enough for two or more lines of moving vehicles in each direction, and on a one-way street or roadway restricted to one direction of movement that is free from obstructions and similarly wide. Section 2202.6 caps it, allowing a right-side pass only under conditions permitting the movement in safety and never by driving off the pavement or main-traveled portion of the roadway. None of these authorises passing inside the overtaken vehicle's own lane.

Now the contrast that settles the question. Chapter 12 of Title 18 gives bicycles and motorized bicycles their own operating rules, and § 1201.3(b) says a person operating a bicycle or motorized bicycle may overtake and pass other vehicles on the left or right side, staying in the same lane as the overtaken vehicle, or changing to a different lane, or riding off the roadway, as necessary to pass with safety. Section 1201.3(c) goes further: where a lane is partly occupied by vehicles that are stopped, standing or parked, that rider may ride in that lane or in the next adjacent lane used by vehicles proceeding in the same direction. That is filtering, written out in full, and granted to a defined class that does not include motorcycles.

The class line is drawn by the machine, and in the District it can shift while you ride. A motorized bicycle is defined as a vehicle with a post-mounted seat, two or three wheels at least sixteen inches in diameter, fully operative pedals for human propulsion, and a motor incapable of propelling it at more than twenty miles per hour on level ground. The same definitions section then provides that a motorized bicycle becomes a motor-driven cycle when operated by motor above twenty miles per hour, and becomes a motorcycle when operated by motor above thirty miles per hour. So a pedal-equipped moped creeping past stopped traffic is exercising a right § 1201.3 gives it, while the same rider above thirty miles per hour is a motorcyclist with no such right. A twist of the throttle changes which rulebook applies.

Lane splitting in the District is charged under the ordinary lane and passing rules rather than a dedicated offence. 00. 00. 00, which is a realistic companion charge when a rider threads a queue. 1 lets the Director reserve any lane for a single class of vehicle by posted sign. C. C. 03.