The MBTA’s expansive service and prominent regional position mean it has significant potential to alleviate congestion and mitigate greenhouse gas (GHG) emissions from single-occupancy vehicles through mode shift—trips taken on transit that may have otherwise been taken by car. Measures such as MBTA ridership provide context for mode shift, while GHG emissions reductions and bus electrification efforts work to advance healthy and sustainable transportation in the region. A new electricity procurement contract supplied by 100 percent renewable energy sources went into effect on January 1, 2021. This purchase has resulted in complete avoidance of the 36 percent of the MBTA’s GHG emissions that typically come from electricity usage.
Ridership measures the number of rides the MBTA system provides each year. In accordance with industry standard, ridership is measured as unlinked passenger trips (UPT), which reflect each time a passenger boards a transit vehicle. Unlinked passenger trips include estimates for trips that are not directly measured, such as transfers that do not involve fare equipment and trips in which riders do not interact with the fare system. Ridership estimates for FY22 may be adjusted slightly in the future.
Riders completed a total of 203 million unlinked passenger trips across all MBTA services in FY22, or roughly 641,000 UPT on an average weekday. This represents a 71 percent increase from 119 million UPT in FY21, which is a significant increase but still 44 percent lower than the 363 million UPT seen in FY19, primarily due to the COVID-19 pandemic. All modes increased ridership in FY22 compared to FY21. Bus service retained the highest proportion of its ridership throughout the pandemic and increased UPT by 41 percent in FY22 over FY21. Ferry, light rail, and commuter rail had the largest ridership increases in FY22 compared to FY21, at 247 percent, 200 percent, and 107 percent, respectively. Heavy rail ridership increased 76 percent in FY22 over FY21. The RIDE had the smallest increase of 27 percent higher UPT in FY22 than FY21.
Ridership estimates for FY22 may be adjusted slightly in the future. Ridership may not match annual and monthly ridership estimates reported to the National Transit Database (NTD) due to new data that may become available after reports are submitted, such as from Green Line vehicles. The most current ridership estimates can be found on the MBTA Performance Dashboard.
Greenhouse gas (GHG) emissions are reported as the MBTA’s total GHG emissions in kilograms of carbon dioxide equivalent (kg CO2e) and as the rate normalized by total unlinked passenger trips (UPT). This measure does not account for GHG savings acquired via mode shift, from trips taken on transit rather than in single-occupancy vehicles, which is estimated to be at least four times larger than net emissions.
A new electricity procurement contract supplied by 100 percent renewable energy sources went into effect on January 1, 2021—as a result, the 36 percent of the MBTA’s GHG emissions that typically come from electricity usage have been avoided. In FY22, the MBTA emitted 216 million kg CO2e, a significant decrease from 287 million kg CO2e in FY21, primarily due to being the first full fiscal year with 100% renewable electricity supply. The Commonwealth of Massachusetts aims to reduce GHG emissions by 80 percent by 2050 compared to 2005 levels—the MBTA is on track to exceed that goal. Since 2009 the MBTA has reduced its GHG emissions by 43% and is targeting 50% reduction by 2030 and Net-zero by 2050. The rate of GHG emissions was 1.06 kg CO2e per UPT, a decrease from 2.41 in FY21. This decreased rate of emissions is less than the rate from 2021, 2020, and 2019. Ridership estimates for FY22 may be adjusted slightly in the future.
Bus fleet composition measures the proportions of the MBTA bus fleet that are electric, hybrid, utilize compressed natural gas (CNG), or diesel fuel sources. Buses classified as electric include battery-electric buses and electric trolley buses, while buses classified as hybrid—with both electric and conventional fuel options—include traditional hybrid buses and Dual Mode Silver Line buses. In FY22, the MBTA’s roughly 1,300-bus fleet was 0.4 percent electric, 47.6 percent hybrid, 15.4 percent CNG, and 36.5 percent diesel.
Bus fleet composition particularly impacts residents living near bus routes due to criteria air pollutants emitted. While diesel-only buses emit higher levels of criteria air pollutants, alternative fuel buses (including electric, CNG, and hybrid) can mitigate air pollution caused by buses for nearby residents. Of residents living within a quarter mile of MBTA bus routes in FY22, roughly 49 percent were near routes running alternative fuel vehicles, 43 percent were near routes running vehicles of mixed fuel types, and 9 percent were near routes running diesel-only buses. Of low-income households within a quarter mile of MBTA bus routes, roughly 50 percent were near alternative fuel routes, and 8 percent were near diesel-only routes. Of residents of color living near MBTA bus routes, 45 percent were near alternative fuel routes and 8 percent were near diesel-only routes.