Center transitways are used with high-quality, frequent bus or rail service on very large streets.
Where right-side boarding is required, such as for BRT services that also operate in curbside lanes, center transitways with right-side medians are a flexible option.
When left-side boarding is available, center transitways can be designed either along a median or on the median, with center-median stations.
Center transitways, especially those separated by medians or raised above the roadway surface, provide very strong protection from traffic-related delays, both from friction between lanes and from unauthorized use of transit lanes.
Central transitways allow the highest running speeds among on-street transit facilities, since pedestrians interact with vehicles only at stations and crosswalks, and bicycle use of the transitway is prohibited. Placing buses in separated space in the center of a roadway improves travel time and reliability by reducing conflicts with parked cars, bicycles, and right-turn movements.
Median space can be used for stations, green infrastructure, greenways/multi-use paths, or other public spaces, depending on width.
Placed in the median of a multi-lane roadway, center-running rail lines can provide the most robust transit service thanks to dedicated lanes, larger stations, and high-capacity vehicles.
Transit speed and reliability on transitways is limited primarily by dwell time. Key rapid transit elements, such as off-board fare payment, all-door boarding, and level or near-level boarding, should be applied to maximize the benefit of a median transitway.
Transit vehicles with only right-side doors must either use right-side platforms at stations, or use a contraflow bus configuration with center-boarding islands.
Stations for center-median transitways may take up more right-of-way width than curbside-running lanes, since boarding platforms and median strips must be placed between the transitway and travel lanes.
Right-boarding BRT stations allow the use of typical rolling stock, which often run on streets without dedicated lanes at the beginning or ends of their routes.
Center platforms may reduce overall space occupied by stations, though side-boarding islands can have space benefits when stations are split across an intersection.
Installation should be coordinated with land use changes that maximize potential for transit-oriented development. Land use regulations should be tailored to promote transit use and create a more inviting pedestrian realm.
Left-boarding center-median stations reduce this space consumption significantly.