Fleet

5

TECHNOLOGY

This section addresses the various technology systems incorporated into a BRT system, including fleet, fare system, and traffic signal control and relevant considerations for the Everett‒Boston corridor.69

FLEET

BRT vehicle selection is complex and depends on a variety of considerations, including operational, legal, institutional, and strategic factors.

VEHICLE SELECTION: BODY DESIGN

DETERMINE VEHICLE BODY SPECIFICATIONS

Using 60-foot articulated buses on the Everett‒Boston BRT corridor will increase vehicle carrying capacity and allow a smaller fleet (compared to 40-foot buses) to meet the expected passenger demand. This vehicle type is familiar to the MBTA, as its fleet already includes articulated 60-foot buses on the Silver Line and other high-capacity routes. Because of steep grades on parts of the route, especially in Everett, buses with dual-powered axles would be required for winter travel conditions. In addition, stops and street geometry on other local portions of the route would need to be analyzed for compatibility with 60-foot buses.

DETERMINE DOOR POSITION (LEFT, RIGHT)

The proposed BRT is envisioned with a direct service model in which several BRT routes continue off the busway and service curbside bus stops (see Operations/Service Planning). As a result, all BRT buses will require at least right-hand doors. If the BRT stations are aligned to the inside (right) of the bus-only lanes, then passengers can board through the right-hand doors. Alternatively, if the BRT stations are aligned to the outside (left) of the bus-only lane, the BRT buses will also require left-hand doors. (See section Roadway and Station Configuration for a discussion about the trade-offs between left- and right-side stations.)

DETERMINE NUMBER OF PASSENGER DOORS

The number of passenger doors also needs to be selected—two, three, or four. The MBTA’s 60-foot fleet has three doors on the right side, allowing increased passenger flow compared to two doors. There are some examples of 60-foot buses with four doors on each side, notably Van Hool buses operated by AC Transit in Oakland.70

VEHICLE SELECTION: FUEL AND PROPULSION

SELECT A ZERO-EMISSION BUS TECHNOLOGY

Transportation accounts for nearly one-third of Boston’s greenhouse gas emissions, and Broadway and Rutherford have among the highest vehicle emissions levels in the region. Massachusetts’ most vulnerable populations— Black residents, individuals with lower education, and households with an annual income of less than $20,000—are burdened with exposure to higher concentrations of local air pollutants.71 To address this inequity, zero-emission buses should be prioritized for this BRT corridor that serves Environmental Justice72 communities in Everett and Boston.

The MBTA buses that currently connect Everett to Sullivan Square (routes 104, 105, and 109) are diesel-powered, so shifting this corridor to electric-powered transit would result in a net reduction in emissions of local air pollutants and greenhouse gases, helping to address local public health disparities and address climate change.

ITDP examined two types of electric buses for this BRT corridor: batteryelectric buses (BEB) and electric trolleybuses. More discussion of the tradeoffs between BEBs and electric trolleybuses is available in Appendix L. To summarize the primary considerations for fleet selection:

Operational Range. The battery range of a BEB determines how long it can operate between charges. Other U.S. cities’ experience with articulated BEBs underscore that battery technology is improving but not yet meeting transit operational requirements.73 Electric trolleybuses would require installation of overhead catenary wires, which are infeasible on the Alford Street Bridge but would be unable to continue off-corridor to Cambridge/Somerville as the service plan requires.

Fleet procurement. Converting the fleet to battery buses may require additional fleet. Overnight-charge battery buses may not have enough range to provide a full day of service.74

Recharging. With the installation of in-route chargers, BEBs can partially recharge during service, but they will need to fully recharge overnight at a garage with charging infrastructure. Electric buses using opportunity charging facilities at route termini may be feasible for some of the routes75 served on the corridor and could be studied further. Because of several corridor geometric issues, in-motion charging is not likely appropriate for the Everett‒Boston corridor.

Winter traction. MBTA’s current 60-foot articulated buses are often removed from service during snowy conditions as they are likely to lose traction and slip.76 There are some steep grades on the EverettBoston BRT corridor, so the BRT fleet will require domestically available articulated buses with a second, powered axle to improve safety and performance in winter.