Compared to other major North American cities, New York City has a smaller number of low-emission buses – with Los Angeles Metropolitan Transportation Authority having around 2,000 CNG and 50 battery electric buses in service, and the Toronto Transit Commission having around 600 hybrid and 210 electric buses in service.[2][3] Compared to cities internationally, New York City also has a smaller number of low-emission buses, with Moscow, London and Paris having 2,700, 2,000 and 1,100 electric buses in service respectively.[4][5][6]
The Metropolitan Transportation Authority (MTA) notes that they expect to purchase only zero-emission buses from 2029 onwards, and aim to have a fully zero-emission bus fleet by 2040.[7]
Asthma disproportionately affects low-income residents and communities of color, with hospitalization rates nearly 10 times higher.[14] Since the 1970s, New York City has worked to improve air quality, with reduced levels of particulate pollution, nitrogen oxides and sulfur dioxides in the city, as well as fewer smog-alert days.[15][16]
New York City has set a target of reducing greenhouse gas emissions by 80% by 2050.[17] Transport is the second-highest source of greenhouse gas emissions in New York City — with the majority from gasoline and diesel vehicles.[18] In 2019, New York State signed the Climate Leadership and Community Protection Act in law, which sets goals to reduce emissions to 40% below 1990 levels by 2030 and then to 85% below 1990 levels by 2050.[19]
As of 2025[update], there are several alternatives to diesel transit buses that produce less emissions and particulate pollution.[1]
Compressed natural gas buses are powered by compressed natural gas (CNG), with lower tailpipe carbon dioxide (CO2) emissions and significantly less particulate pollution than diesel buses. CNG is also cheaper than diesel fuel.
Hybrid electric buses use a combination of an electric battery pack and a diesel engine to provide power, and produce around 40% less CO2 emissions than traditional diesel engined buses. Energy recovered during braking is used to charge the batteries of hybrid vehicles.
Battery electric buses use on-board batteries to power an electric motor that drives the bus. Unlike a hybrid electric bus, there are no local emissions. As with hybrid buses, regenerative braking is used to charge the batteries.
Hydrogen fuel cell buses use the reaction of hydrogen with oxygen to generate electricity that drives the bus with an electric motor. The only emission from the bus is water.
In 1986, it was announced that the MTA would trial methanol fuel,[21][22] with buses entering service in 1992. Other cities also trialed methanol buses, with Los Angeles purchasing over 300 – but suffered a high number of engine failures.[23][24] MTA withdrew its methanol buses in 1995, after "[recognizing methanol] was no longer a viable option for future bus purchases".[24]
In 1992, New York City Transit Authority (NYCT) began trialing buses powered by compressed natural gas (CNG).[25][26] Although less polluting than diesel buses, officials noted that CNG buses were around $42,000 more expensive and that depots would need to be modified to handle CNG.[27] In 1996, a reluctant MTA agreed to replace more diesel buses with CNG buses, following pressure from Governor George Pataki and New York State SenatorNorman J. Levy.[28] Mass-ordering of CNG buses began in 1999, and over 220 CNG buses were in service by 2001.[29] The Natural Resources Defense Council noted that CNG buses are not pollution free, but they're "clearly the best choice among the commercially available options".[30]
In 1997, West Harlem Environmental Action launched the "Dirty Diesel" campaign to push the MTA to purchase cleaner diesel and CNG buses, following a report from the Environmental Protection Agency that indicated that levels of air pollution in Northern Manhattan exceeded federal standards by "as much as 200 percent".[31][32] In 1999, several campaign groups including Natural Resources Defense Council, the Regional Plan Association and the New York State branch of the American Lung Association criticized the MTA's progress at introducing clean buses, stating that delays will "subject New Yorkers to [...] unacceptably high diesel fumes and unnecessarily high health impacts".[33] In November 2000, West Harlem Environmental Action filed a complaint with the US Department of Transportation (USDOT), claiming that bus depots were "disproportionately located in minority communities", leading to health risks owing to "high exposure to harmful diesel exhaust".[34][32] The USDOT found that the MTA violated Title IV of the Civil Rights Act of 1964 and failed to meet the federal environmental impact analysis involving the construction, rehabilitation, and operation of bus depots and other facilities.[35]
In April 2000, the MTA and state lawmakers agreed an uplift in the percentage of new CNG or hybrid buses purchased as part of the 2000-2004 Capital Plan.[36][37] Under the agreement, around 44% of new bus purchases would be CNG or hybrid buses, an uplift of 16%.[37] In June 2000, the MTA established a "Clean Fuel Bus" program.[38] Cleaner diesel buses were purchased, older buses had their engines replaced, and all buses began to use ultra-low-sulfur diesel in combination with the fitment of diesel particulate filters.[10][39][40] By 2003, all buses were fitted with diesel particulate filters.[39] The MTA noted that their purchase of millions of gallons of ultra-low-sulfur diesel meant that there was enough demand for it to be produced in the United States at a cheaper cost, rather than having to be imported from a refinery in Rotterdam, Netherlands.[39] This led to other transit agencies in the United States including Massachusetts Bay Transportation Authority and NJ Transit to start using ultra-low-sulfur diesel.[39]
By 2002, The New York Times reported that "it is now hard to spot a city bus trailing even a modest cloud of black smoke", and that "environmentalists [...] seem impressed by the progress the agency has made toward meeting the goals set in Albany to improve the city's air".[39] By 2006, particulate emissions had fallen by 290 tons from 1995 levels (a reduction of 97%), with nitrogen oxide emissions falling by 2,781 tons from 1995 levels (a reduction of 47%). Researchers noted that this improvement in emissions occurred despite a 27% increase in the number of buses, and a 17% increase in the number of miles driven.[40]
Introduction of hybrids
Orion VII NG hybrid-electric bus, operated between 2008 and 2024
In September 1998, the MTA began to trial hybrid-electric buses, which operate with a combination of diesel and electric power.[41][42] The Orion VI hybrid buses purchased by the MTA cost around $1 million each, substantially more than an equivalent sized diesel or CNG bus.[42] However, replacing diesel buses with CNG ones require expensive improvements to bus depots.[35][42]
From 2003, the MTA began to order hybrid buses en-masse, purchasing the Orion VII.[43] These entered regular service from April 2004.[35] In 2005, the MTA announced plans to purchase hybrid buses in future instead of CNG buses, noting the cost of upgrading bus depots.[35] By 2009, over 850 hybrid buses were in service, around 19% of the bus fleet.[42] The MTA noted that by 2010, they would have the "largest diesel-electric hybrid fleet in the world" with over 1,700 buses.[44]
In 2008, research by the National Renewable Energy Laboratory showed that second generation hybrid buses (those ordered from 2006 onwards) cost around 40% less to maintain than earlier hybrid units, with comparable maintenance costs to CNG buses. It also showed that they cost 24% less to operate than earlier hybrid buses, owing to improved fuel economy (3.00 to 3.22mpg‑US (0.78 to 0.73L/km)). This was also more fuel efficient than the 2.33mpg‑US (1.01L/km) diesel equivalent for the CNG buses.[45][46]
In 2013, media reported that the MTA was considering replacing out of warranty hybrid units with new diesel engines, with sources stating that the hybrids were less reliable than diesel buses.[47]
In 2016, Columbia University published a report commissioned by NYCT that analyzed the possibility of transitioning to an electric bus fleet. The report noted that:[49][50]
electric buses (and the required charging infrastructure) cost around $300k more to purchase than diesel buses
electric buses are around $39k cheaper to run per year, given the lower cost of electricity compared to diesel or CNG fuel
savings associated with fuel and bus maintenance "more than offsets the higher [upfront] cost of electric buses"
an all-electric fleet would lead to a reduction of emissions within the city of "approximately 575,000 metric tons of CO2e per year"
health benefits from the elimination of air pollution caused by diesel fuel combustion was estimated at $150k per bus
a number of cities around the world are considering changing to electric buses
The report concluded that the city should "take the first steps towards purchasing electric buses", in light of the financial savings and that the resulting "health benefits and greenhouse gas reductions are [...] compelling".[49]
In January 2018, Governor Andrew Cuomo announced that the MTA would test electric buses on a three year trial, running on bus routes in Brooklyn, Queens and midtown Manhattan.[51] Ten 40-foot battery electric buses were leased – five from New Flyer and five from Proterra, the XE40 Xcelsior CHARGE and Catalyst BE40 models respectively.[52] The MTA noted that it planned to order 60 electric buses in a future testing phase, depending on the results of the initial trials.[51] The leases expired in 2021,[53] with the MTA noting that they had learnt several things from the trial including that:[54]
each manufacturer has "proprietary charging protocols"
batteries could only support one-third of existing schedules, due to insufficient range
air temperature affects battery range
New FlyerXE60 battery-electric articulated bus being charged
In 2019, MTA purchased zero-emission buses for the first time — ordering 15 battery-electric 60-foot articulated buses from New Flyer. These entered service in 2020, primarily Manhattan Select Bus Service routes. In September 2019, the MTA Board approved its 2020–2024 Capital Plan, which included $1.1 billion to purchase 500 electric buses and retrofit eight bus depots with charging equipment.[58][59] In 2020, the MTA announced that it would be purchasing renewable natural gas for its CNG buses, with the natural gas produced from organic waste.[60] In 2021, the MTA purchased 135 diesel buses from Nova Bus, noting that they would continue to purchase diesel buses until 2028 — despite the plan for a fully electric bus fleet by 2040.[61]
In April 2021, the MTA placed an request for proposals for 45 new 40-foot battery-electric buses.[53] Later in 2021, the MTA awarded New Flyer the contract for the electric bus order, set to arrive in late 2022 and 2023. Fifteen more buses were added to the originally 45-bus contract, making for a total of 60 buses allotted for NYCT;[53] these were delivered in 2024.[62][63]
In May 2022, the MTA published its Zero-Emission Bus Transition Plan which set out a plan for transitioning the bus fleet to zero emissions, as well as setting out the challenges and issues of such a transition.[64] This was updated in 2024, setting out a phased approach to reach a 100% zero-emission bus fleet.[65] In April 2025, the MTA Board approved the 2025-2029 Capital Plan, which includes funds to expand the fleet to over 1,000 battery electric buses, as well as work to retrofit existing bus depots.[7][66] In June 2025, media reported that New Flyer battery electric buses were not as reliable in service as diesel buses.[67]
Future plans
The number of zero-emission buses is due to increase to 1,035 by 2029.[7] The MTA is aiming for the entire bus fleet to be zero emission by 2040,[7][68] although in 2023 MTA officials expressed doubts that the fleet would be fully electrified by that date.[69]
There are 967 hybrid buses, 732 compressed natural gas (CNG) buses and 15 battery electric buses operating in New York City as of June2023[update] — amounting to around 30% of the city's fleet of around 5,700 buses.[1] In 2022, an academic study showed that the MTA's increased use of CNG and hybrid-electric buses between 2009 and 2014 led to improvements in air pollution across the city, including a reduction in nitrogen oxides.[72]
↑National Center for Environmental Assessment, Washington, DC, for the Office of Transportation and Air Quality (2002). Health assessment document for diesel exhaust (Report). U.S. Environmental Protection Agency.
↑Pierre-Pierre, Garry (January 16, 1996). "Buses Using Natural Gas Do Well in Pilot Program". The New York Times. Retrieved October 30, 2025. New York City buses have long been notorious for the black soot many of them spew out of their exhaust pipes
↑Hu, Winnie; Gavrielov, Nadav; Ewing, Jack (April 5, 2022). "Here's How Slowly New York City Is Moving on Electric Vehicles". The New York Times. ISSN0362-4331. Retrieved June 18, 2025. The Metropolitan Transportation Authority, which runs the city's buses, plans to spend $1.1 billion to buy another 500 electric buses and retrofit eight bus depots with charging equipment to try to achieve a goal of a zero-emissions bus fleet by 2040. Riders could see another 60 electric buses on the road as soon as next year.
↑"900 New E-Buses To Be Rolled Out Soon". The Times of India. March 19, 2025. ISSN0971-8257. Retrieved December 28, 2025. The DTC fleet has 1,231 AC CNG buses, 1,878 non-AC CNG buses and 1,250 electric low-floor buses.
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