The trade-offs between center platforms that board from the left or right side are primarily width, capital costs, and fleet compatibility (see Table 4). A single shared center platform can reduce construction costs but is wider and requires buses with left-hand doors which MBTA’s current fleet does not have. Generally, the longer-term operational efficiencies and capital costs should be prioritized over shorter-term fleet compatibility issues.53 MBTA may need to procure additional buses to operate the Everett-Boston BRT routes at the proposed frequencies in any case, so choosing the BRT station alignment based on the existing fleet is shortsighted. Everett and Boston staff, in consultation with MBTA, will need to select a preferred station alignment (inside or outside), while the station platform configurations will need to be optimized for each station location. Table 4: Considerations for Left- and Right-Side-Boarding Center Station Platforms
+
LEFT-SIDE BOARDING
+
Allows larger left-side-door fleet for use in Harvard Tunnel Busway54
-
Existing Silver Line buses and the rest of the MBTA fleet with right-side doors will be incompatible with these stations.
+
RIGHT-SIDE BOARDING
Possibly lower station capital costs of constructing one shared center platform versus two split stations.
Compatible with Chelsea Busway: BRT route could begin at Glenwood, enter Chelsea Busway, and continue to downtown.
+
Does not require MBTA to purchase and maintain another BRT sub-fleet.
-
Possibly higher station capital costs because two platforms, canopies, etc., are required.
ROADWAY DESIGN As BRT ridership grows, especially in space-constrained corridors, the system must be planned so that successful implementation and high demand do not cause a reduction in the transit level of service provided. In the Everett corridor, care should be taken to make sure that the infrastructure built does not preclude future speed or capacity, as has been the case on the Silver Line (see Appendix C). Subsequent sections describe some of the roadway design options and constraints for segments of the BRT corridor. This roadway design discussion assumes that the BRT corridor begins with bus lanes in some configuration at Everett’s Glendale Square and continues along Broadway, crosses the Alford Street Bridge, serves Sullivan Square, continues along Rutherford Avenue, crosses the North Washington Street Bridge, and terminates at Haymarket. This includes the bus priority lanes bypassing traffic at Sweetser Circle, implemented in winter 2020, and at least the southbound bus-only lane planned for the reconstructed North Washington Street Bridge. 53 54
50
Carrigan, Wallerce, and Kodransky 2019. The MBTA has operated a fleet with left-side doors since the 1930s, because of the need to board passengers from the platform in the Harvard Busway. When the 77 bus and other lines were converted to diesel buses in the 1950s, the diesels were not given left-side doors, and southbound buses in the tunnel using diesels to this day drop passengers off on the “wrong” side of the tunnel, requiring them to cross the active busway to access the curb. Operating buses with left-side doors on the Everett-Boston BRT corridor would allow the MBTA to acquire a larger fleet to improve operations for bus lines serving the Harvard Busway and to eliminate this archaic practice.
