Emissions on the Road: Environmental Impact of Automobiles and the Benefits of Going Green

Updated: July 30, 2026

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Vehicles affect the environment. The Environmental Protection Agency (EPA) reports that transportation activities produced 29% of U.S. greenhouse gas emissions in 2021. These emissions cause air pollution, climate change and global warming, issues that affect your health and finances.

The financial impacts show up in your bills for food, utilities, gas, health care and insurance. Extreme weather events can cost you income or even your home. Climate change demands more responsible choices about the vehicles we use.

Your driving habits contribute to global warming. Switching to environmentally friendly vehicles can reduce emissions and lower your auto insurance costs.

Vehicles and Global Warming Statistics

Vehicle emissions are among the largest contributors to greenhouse gas emissions in the country. The impact of climate change poses environmental, economic and financial risks.

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The U.S. recorded a total of 5.6 million metric tons of carbon dioxide (CO2) equivalent in net greenhouse gas emissions in 2021. Transportation was 29% of total emissions.

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In the U.S., about 79% of total emissions are from CO2. The average passenger vehicle emits 4.6 metric tons of CO2 a year on average.

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Aside from CO2, motor vehicles emit other greenhouse gases like methane and nitrous oxide. In the U.S., methane contributed 12% of emissions and nitrous oxide accounted for 6%.

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Since 2010, we've seen the 10 warmest years on record, nine of which occurred between 2014 and 2022. Countries across the globe continue to record higher-than-average temperatures and weather anomalies.

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Climate change poses an economic threat in terms of agricultural productivity, energy use and demand, labor supply, mortality and storm activity. Severe heat waves, coastal flooding and other weather disasters cost the country more than $165 billion in 2022.

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On a personal level, climate change heightens financial risks in real estate, insurance, asset values, investments and cash flows.

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How Much Greenhouse Gas Is Released by Vehicles?

Greenhouse gas emissions, including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions, harm the environment. In the U.S., transportation activities cause the most emissions at 29%. According to the EPA, the average passenger vehicle emits 4.6 metric tons of CO2 a year.

Net emissions increased by 6% compared to the 2021 total, mainly due to increased economic activity after the COVID-19 pandemic slowdown. Transportation sector emissions grew 19% from 1990 to 2021.

Carbon dioxide emissions from energy consumption fluctuate as consumption levels change. Petroleum remains the highest contributor to CO2 emissions in the transportation sector. Natural gas emissions are much lower but have grown steadily.

Sources of CO2 Emissions in the Transportation Sector

CO₂ emissions from transport energy use, 2000–2022, showing petroleum dominance and slight rise post-2020.

Greenhouse Gas Emissions by Sector

In 2021, the transportation industry had the highest greenhouse gas emissions in the country among all economic sectors, up 18.6% since 1990. Emissions increased year-over-year as economic activity grew and dropped after the COVID-19 pandemic slowdown in 2020. The 2021 total was slightly lower than the 2016–2019 numbers but trended upward. Greenhouse gas emissions in the transportation sector peaked in 2007 at 1,967.25 million metric tons of carbon dioxide equivalent.

Transportation Contributes the Most Greenhouse Gas Emissions in 2021

Stacked chart of U.S. CO₂ emissions by sector from 1990–2021, with transportation as the top emitter.

Transportation CO2 Emissions by State

In 2020, Texas recorded the highest energy-related CO2 emissions in the U.S., with 624 million metric tons, including 192.7 million metric tons from transportation. Vermont had the lowest total CO2 emissions, recording only 5.6 million metric tons, with transportation-related emissions accounting for 2.9 million metric tons.

Emissions Across Vehicle Types

Vehicles are among the largest contributors to greenhouse gas emissions, but not all vehicles emit the same amount. Factors such as engine technology, fuel type, usage patterns and vehicle size all affect emissions. Among on-road vehicles, light-duty trucks had the highest greenhouse gas emissions in 2021 at 671.8 million metric tons of CO2 equivalent. They were followed by medium-duty and heavy-duty trucks (417.1 million metric tons), passenger cars (374.2 million metric tons), buses (25.7 million metric tons) and motorcycles (7.5 million metric tons).

Passenger cars

These include light-duty vehicles with a maximum gross vehicle weight rating (GVWR) of less than 8,500 lbs. and medium-duty vehicles (8,501 to 10,000 lbs.). The EPA considers a vehicle a passenger car if it's primarily used for transporting 12 people or fewer. In 2021, passenger cars recorded the third-highest greenhouse gas emissions among on-road vehicles at 374.2 million metric tons. Beyond vehicle type, emissions vary by fuel type.

The Bureau of Transportation Statistics (BTS) breaks down light-duty vehicle emission rates by fuel type.

Estimated Average Emission Rate (Grams per mile)
Gasoline
Diesel

Total hydrocarbons (HC)

0.280

0.143

Exhaust carbon monoxide (CO)

4.152

3.640

Exhaust nitrogen oxides (NOx)

0.192

0.129

Exhaust particulate matter with diameter <= 2.5 micrometers (PM2.5)

0.004

0.002

Brake wear PM2.5

0.003

0.003

Light-duty trucks

Light-duty trucks, including sport utility vehicles (SUVs) and minivans, carry passengers and cargo. In 2021, light-duty trucks across the country produced 671.8 million metric tons of CO2 equivalent emissions and traveled more than 1,492,200 million miles.

Gasoline-fueled light-duty trucks produce higher emission rates than diesel-fueled trucks across most pollutant categories.

Estimated Average Emission Rate (Grams per mile)
Gasoline
Diesel

Total HC

0.339

0.308

Exhaust CO

5.422

2.458

Exhaust NOx

0.376

1.804

Exhaust PM2.5

0.007

0.078

Brake wear PM2.5

0.003

0.003

Medium-duty and heavy-duty trucks

Medium-duty and heavy-duty trucks produced 417.1 million metric tons of CO2 equivalent in 2021, the second-largest share among on-road vehicles. These vehicles traveled 317,245 million miles that year. This category includes single-unit trucks, combination trucks, tractor-trailers and box trucks used for freight transportation, plus service and utility trucks.

Gasoline-fueled heavy-duty vehicles produce higher HC and CO emission rates, while diesel-fueled trucks produce more NOx and PM2.5.

Estimated Average Emission Rate (Grams per mile)
Gasoline
Diesel

Total HC

1.161

0.269

Exhaust CO

14.894

2.000

Exhaust NOx

0.875

4.169

Exhaust PM2.5

0.026

0.106

Brake wear PM2.5

0.006

0.009

Buses

Buses were the fourth-highest contributor to greenhouse gas emissions. They totaled 25.7 million metric tons of CO2 equivalent or 1.3% of all emissions. Bus emissions break down as 25.1 million metric tons of CO2, 0.2 million metric tons of nitrous oxide and 0.4 million metric tons of hydrofluorocarbons (HFC).

Motorcycles

Motorcycles had the lowest greenhouse gas emissions among on-road vehicles. In 2021, motorcycles totaled 7.5 million metric tons of CO2 equivalent. The EPA reports these average emission rates for motorcycles:

Estimated Average Emission Rate (Grams per mile)
Gasoline

Total HC

2.624

Exhaust CO

13.411

Exhaust NOx

0.642

Exhaust PM2.5

0.021

Brake wear PM2.5

0.002

Illustration of three cars in a city with a person driving a black car in the foreground.

Far-Reaching Impacts of Automobile Emissions

In 2022, the world recorded its sixth-warmest year since 1880, ten of which have occurred since 2010. During this period, the world has seen climate anomalies like rising seas, droughts and severe flooding. Long-term temperature changes result from global warming caused by greenhouse gas emissions. Motor vehicles are among the country's highest-emitting sources. In the U.S., the transportation industry has the highest impact among all economic sectors.

The effects of car emissions extend beyond weather-related events. Climate change has an indirect effect on the economy, health and personal finance. Home values decrease, utility bills increase, and insurance costs rise as extreme weather events create a greater risk of property damage.

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    Air pollution

    Burning fossil fuels, including the gasoline and diesel that power cars, releases pollutants such as particulate matter (PM) and volatile organic compounds (VOCs) into the air. Vehicle emissions also cause greenhouse gases like CO2, NOx, CH4, N2O and HFC to build up. These gases worsen air quality and warm Earth's atmosphere.

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    Health impacts

    Exposure to pollutants like PM and VOCs, as well as greenhouse gases, may lead to respiratory problems, cardiovascular disease and increased cancer risk.

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    Environmental degradation

    Pollution from vehicle emissions also spreads to soil and water. Greenhouse gases deplete the ozone layer and reduce Earth's protection against ultraviolet radiation. When greenhouse gases mix with rainwater, they create acid rain that harms plants and wildlife. Oil spills from vehicles penetrate the soil, and PM from emissions contaminates bodies of water.

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    Noise pollution

    Humans and wildlife may develop health issues from vehicle noise pollution. Regular exposure can disturb sleep patterns, cause stress and even increase the risk of developing heart disease.

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    Economic costs

    Economic implications of vehicle emissions include higher health care costs due to pollution-related diseases, additional expenses for infrastructure maintenance, material losses from extreme weather events, higher utility bills and increases in home insurance premiums.

Cars parked in a city with trees and a woman standing nearby in a minimalist illustration.

Driving Green: How to Reduce Emissions

Passenger vehicles are among the largest sources of greenhouse gas emissions and a leading driver of global warming. This isn't exclusive to the U.S. The transportation sector contributes 16.2% of all greenhouse gas emissions globally. Of these, 11.9% are from on-road vehicles.

Car emissions drop when drivers choose fuel-efficient vehicles, drive less and adopt eco-friendly habits. The result: cleaner air and less dependence on fossil fuels. The United Nations includes sustainable transport in the Sustainable Development Goals under the Paris Agreement on Climate Change.

Car owners can take these steps to reduce their carbon footprints:

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    Regular vehicle maintenance

    Regular maintenance is one of the most effective ways to keep a car running efficiently. Plan regular tune-ups, follow the manufacturer's maintenance schedule and use only recommended products, such as a specific grade of motor oil.

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    Eco-friendly driving practices

    Efficient driving reduces emissions. Take it easy on the gas pedal and brakes. Avoid unnecessary idling, which causes air pollution and excess wear and tear. Monitor your car's temperature and limit air conditioner use to reduce emissions.

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    Finding alternative transportation options

    Ask yourself whether driving is necessary for each trip. For short distances, consider walking or riding a bicycle. Try taking public transit or carpooling with colleagues or friends for longer commutes.

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    Supporting renewable energy sources

    If you're thinking of buying a car or replacing your current vehicle, consider more fuel-efficient vehicles with low emissions like EVs, plug-in hybrid EVs, hydrogen fuel cell vehicles and cleaner-burning gasoline vehicles. These can lower emissions and reduce your fuel costs.

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    Raising awareness and advocating for change

    Supporting advocacy efforts can raise public awareness and encourage more people to participate. You may start with small steps like sharing informational materials and public service campaigns from government agencies and nonprofits.

CARBON FOOTPRINT CALCULATORS

A carbon footprint calculator can help you see the scale of your emissions across home energy, waste and transportation.

You can visit the EPA's Carbon Footprint Calculator and enter your ZIP code and the number of people in your household to get a quick estimate. You may also download a spreadsheet version to see how emissions are calculated. Another option is The Nature Conservancy's online interactive tool.

Reducing Your Carbon Footprint With Green Auto Insurance

Auto insurance provides financial protection against unexpected incidents, though that coverage can come at a high price depending on the policy. Many auto insurance providers offer green or eco-friendly auto insurance that rewards green efforts with discounts. Green car insurance may also refer to programs that allow you to pay premiums based on how much you drive.

Benefits of Green Auto Insurance

Green auto insurance financially rewards drivers for lower-emission choices. Insurers offer specialized coverage for hybrids and electric cars, with higher limits for replacement parts and repairs. Some also cover batteries and power cables or offer incentive programs that lower your premium.

Usage-Based Auto Insurance

For some insurance companies, green auto insurance comes from usage-based policies. You'd only pay for how much you drive: the fewer miles you accumulate, the lower your premium. These programs reward drivers who cut emissions by accelerating smoothly, braking gradually and avoiding peak traffic hours.

Pay-as-you-drive programs install a mileage-tracking device in your vehicle. You get policy discounts when you drive fewer miles than average.

Additional Incentives for Sustainable Driving

Insurance companies reward environmentally friendly transportation choices beyond pay-as-you-drive programs and specialized coverage.

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    Green vehicle premium discounts

    A hybrid or EV may help lower the cost of auto insurance.

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    Alternative fuel premium discounts

    Some insurers offer discounts to drivers using alternative energy sources like biodiesel, natural gas, hydrogen, ethanol or electricity.

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    Green vehicle replacement

    If your gasoline-powered vehicle gets totaled in an accident and you decide to replace it with an electric or hybrid car, green vehicle replacement coverage will help cover the costs.

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    Paperless discount

    Paperless billing can also lower your premium. Many insurers offer this discount.

Woman charging an electric car at a station in a modern, clean environment.

Green Wheels: How to Choose an Environmentally-Friendly Vehicle

More eco-friendly vehicles are on the market today, running on alternative energy or using fuel more efficiently. They produce fewer greenhouse gas emissions and cost less to fuel. These six factors can guide your choice.

  1. 1
    Size and weight

    Lighter vehicles have better aerodynamics and get better gas mileage. Think about how much cargo and how many passengers you'll regularly carry before choosing a model.

  2. 2
    Personal needs and preferences

    Factor in your commute and daily driving habits. Research different classes and models to find one that fits your routine.

  3. 3
    Safety features

    Look for accident prevention features like radar alerts and advanced seat belts.

  4. 4
    Fuel efficiency and emissions

    Check what alternative fuel sources are available near you, including biodiesel, which cuts greenhouse gas emissions. If charging stations are accessible, an electric vehicle may be a good fit. Hybrids give you the flexibility to run on gas or electricity.

  5. 5
    Vehicle lifespan and maintenance

    Conventional cars with internal combustion engines require more regular maintenance than EVs, which need battery pack replacements after several years. Factor long-term upkeep costs into your decision alongside the purchase price.

  6. 6
    Financial considerations

    Set a budget before you start comparing cars. A clear price range upfront keeps your options focused.

Expert Insight on Vehicles and Climate Change

The decision to go green requires commitment. MoneyGeek asked a few industry experts to explain the connection between vehicles and climate change.

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Additional Resources

These resources cover how cars affect global warming and what you can do about it. MoneyGeek compiled the following:

About Nathan Paulus

Nathan Paulus, Head of Content and SEO, MoneyGeek

Nathan Paulus is the Senior Director of Content and SEO at MoneyGeek, where he leads content strategy and produces original data research across insurance, consumer costs, transportation safety, housing, public policy and personal finance. He also reviews published studies for methodology, source quality and factual accuracy before they reach readers.

Research and Analysis

In more than six years at MoneyGeek, Nathan has published more than 100 original studies and explanatory guides. His insurance research includes 50-state comparisons of health care outcomes, costs and access, plus an analysis of how uninsured rates track with state Medicaid expansion decisions and electoral patterns. He has analyzed full coverage auto rates across major insurers in all 50 states and tracked how premium trends relate to industry underwriting losses. The analysis draws on combined ratio data from Fitch Ratings and AM Best, plus Bureau of Labor Statistics CPI figures. Beyond insurance, his work spans vehicle pricing trends across the U.S. new car market, summer traffic fatality rates by state, homeowner underinsurance ratios using mortgage and policy data, and housing affordability across all 50 states.

His research has been cited by Bloomberg, the Los Angeles Times, Forbes, Fast Company, the San Francisco Chronicle, USA Today and NBC Los Angeles. Harvard, MIT, Stanford and Yale have referenced his work.

Career

Nathan traces his interest in personal finance back to his grandmother, who ran her household on a simple rule: spend less than you make and save the difference before anything else. That rule shows up in his work today. His writing skips jargon and complex strategy in favor of the basics that help someone living paycheck to paycheck.

He joined MoneyGeek in July 2020 as Director of Content Marketing, where he led the content team and oversaw data journalism production across insurance and personal finance verticals. A promotion to Head of Marketing and Communications followed in December 2023. The new role added digital PR and communications strategy to his scope. He has held his current position, Head of Content and SEO, since January 2025.

Before MoneyGeek, Nathan served as Director of Content Marketing and SEO at Ventrix Advertising, where he helped build two content sites from scratch, contributed to link-building programs that generated more than 1,500 unique referring domains within a year and co-managed a marketing team of more than 20 people. Two and a half years at ABUV Media preceded that role. He advanced from Marketing Research Analyst to Senior Marketing Tactics Analyst, where he developed skills in audience research, content strategy and SEO.

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