Designate lanes using a single or double solid white line, as well as a stenciled “BUS ONLY” marking (refer to MUTCD 3D.01). In some jurisdictions, markings may be required for each permitted user (e.g. “TAXI, LRT, BUS ONLY”).
Signage must designate the transit lane as restricted. Place signs either on the curbside or overhead (MUTCD 2B.20).
Mark the transit lane with red color. Red color treatments are effective in reinforcing lane designation.
Enforcement is critical to the lane’s integrity. Vehicle-mounted video enforcement has demonstrated efficacy in improving transit lane compliance.
The desired width of a curbside bus lane next to a mixed-traffic lane is 10–12 feet, including a gutterpan if present. Bus-only lanes should not typically exceed 12 feet in width. If target operating speeds between stops are low, typically below 25 mph, 11-foot lanes are preferable to 12-foot lanes. If buses operate in an adjacent lane, a 12-foot curbside lane is desired.
Provision for curbside loading can improve compliance, such as timed freight parking on the other side of the street or around the corner from loading destinations.
At intersections with a high volume of turning movements, the curbside lane may need to drop to maintain traffic flow.
If 13 feet of width is available, full-time curbside bus lanes may be separated with left-side, traversable barriers, such as rumble strips. Separation is not appropriate in all contexts, and must be developed with special care for its impact on walking and bicycling access. If curbing or other hard separation is used, including mountable curbs, bus lanes should be designed to allow passing at selected points. The impact on snowplowing operations should be evaluated when considering the use of curbs to separate the bus lane from other traffic, in climates where snow is a possibility.
Wider sidewalks, especially those buffered with plantings or furnishings, increase pedestrian safety and comfort adjacent to curbside transit lanes.
Curbside lanes may be separated with hard barriers (e.g. concrete curbs), which may be intermittent or continuous. Where nearly continuous, curbs should at least be omitted for short segments to allow buses to pass, or to allow buses to pass break-downs or incursions.
On very high frequency corridors where bus traffic is significant enough to create congestion, double transit lanes can be implemented curbside. The second bus lane should be designed as an offset transit lane.