Designate lanes using BUS ONLY markings and signs (MUTCD 3D-01 or similar markings).
Dedicated transit lanes must be separated from other traffic using solid single stripes or double white stripes. A solid single white line conveys that crossing into the transit lane is discouraged, and typically indicates that using the transit lane to pass is prohibited, whereas a double solid white line means that encroachment is legally prohibited (MUTCD 3B.04).
Enforcement is critical to maintaining the lane’s integrity. Vehicle-mounted photo/video enforcement has been demonstrated to be effective in improving transit lane compliance.
By equipping its entire transit fleet with enforcement cameras, San Francisco’s Muni has seen delay reductions on routes with transit-only lanes ranging from 3 to 15% throughout the day. During afternoon peak, when delay is most significant, Muni has observed even better delay reductions, ranging from 7 to 20%.
San Francisco Municipal Transportation Agency. Transit-Only Lane Enforcement. MuniForward white paper (2015).
Bus lane width should be determined within the overall assemblage of a street, taking into consideration adjacent lane uses, with a desired width of 10–11 feet. At stops, bus lane may narrow to 9 feet.
Red color treatments are effective in reinforcing lane designation. Apply red color along the entire lane.
Transit bulbs should be installed at stops to enable in-lane stops, and provide space for other stop and sidewalk amenities. Curb extensions may be installed at non-stop intersections to increase pedestrian space and shorten crossing distance—interim treatments and materials such as paint, planters, and bollards can be implemented at low cost.
It may be desirable to assign additional space to a buffer or to a parking lane rather than to the bus lane, especially when large vehicles use the parking lane for loading. A 10-foot bus lane provides a predictable operating environment when adjacent to a buffer or bicycle lane on at least one side.
Bus lanes may be wider to calm traffic in other lanes and reduce risk of mirror damage and minor collisions. Since mixed-traffic lanes should not be wider than 11 feet in urban conditions, extra width may be assigned to the transit lane or to a marked buffer if 2 or more feet are available. If adjacent to a buffer or a bike lane, a 10- or 11-foot bus lane should be provided.
To keep bus lanes unobstructed, parking lanes adjacent to an offset bus lane should be 8–9 feet wide in most cases, or up to 10 feet when truck loading zones are designated or curbside deliveries are frequent. 7-foot parking lanes may be used next to 11-foot bus lanes if compliance is high and wider vehicles are not permitted to park.
Provide shared right-turn lanes or right-turn pockets at intersections with moderate to heavy turn volumes. Offset transit lanes can allow other users, including taxis, for-hire vehicles, and bicycles. Use markings and signs to indicate permitted users.