Buses Vs Cars: Who's The Bigger Polluter?

Transportation is a major source of air pollution and climate change, with tailpipe emissions from cars, trucks, and buses accounting for over one-fifth of the United States' global warming pollution. While buses emit more CO2, they are more fuel-efficient than cars, making them a more sustainable option. This is because buses have a better person-miles per gallon rate than single-occupant vehicles. Additionally, fewer cars on the road mean less traffic, resulting in fewer idling cars and reduced vehicle emissions.

Buses emit more CO2, but cars emit more per person

Buses are a more sustainable mode of transportation than cars. While buses emit more CO2 overall, cars emit more per person. This is because buses are more fuel-efficient in terms of person-miles per gallon. If five people drove their cars 25 miles at 25 miles per gallon, each person would emit about one gallon's worth of emissions. In total, that's five gallons of emissions. However, if those same five people travelled by bus, they would only use one gallon of fuel in total, reducing the emissions per person to one-fifth of a gallon.

The number of passengers is a key factor in determining the environmental impact of a mode of transportation. The denser a mode of transport is in terms of passenger use, the more efficient it becomes. For example, a train will use the same amount of energy to move 1,000 people as it will to move 100 people. Therefore, if the train is at full capacity, the pollution per person is significantly reduced.

Buses are also more sustainable than cars because they reduce the number of cars on the road, leading to less traffic, fewer idling cars, and less vehicle emissions. Additionally, buses are more affordable and reliable for commuters, and they are less likely to be involved in fatal accidents than personal vehicles.

While buses are currently mostly diesel-powered, there is a slow introduction of hybrid and electric-powered buses, which will further reduce their environmental impact.

Trains are less polluting per person, but buses attract more passengers

Transportation is a significant contributor to air pollution and climate change, with motor vehicles emitting pollutants such as carbon dioxide, nitrogen oxides, and sulfur dioxides, which have detrimental effects on human health and the environment. While buses and trains are often compared in terms of sustainability, the choice between the two depends on various factors, including passenger capacity and existing infrastructure.

Buses are more sustainable than cars for several reasons. Firstly, they reduce the number of cars on the road, leading to less traffic congestion, fewer idling vehicles, and reduced vehicle emissions. Additionally, buses offer a safer and more affordable commuting option. However, most buses are diesel-powered, emitting carbon dioxide at a higher rate than cars per gallon of fuel. Nevertheless, buses have better person-miles per gallon rates than cars. For instance, five people commuting 25 miles in separate cars would emit five gallons' worth of emissions, whereas the same people travelling in a bus would only emit one gallon's worth of emissions.

On the other hand, trains become more efficient in terms of energy expenditure as the number of passengers increases. According to Yonah Freemark of the Urban Institute, a train uses virtually the same amount of energy to transport 100 or 1,000 people, so a fully occupied train produces significantly less pollution per person. However, trains often operate below full capacity, and the infrastructure required for rail service can be costly and carbon-intensive to build.

In the United States, buses currently attract more passengers than trains, with double the ridership of Amtrak. Therefore, buses are currently a more attractive option for reducing pollution per person. However, this could change if reforms are implemented to make train travel more appealing to a larger number of passengers.

In conclusion, while trains have the potential to be less polluting per person if fully occupied, buses currently attract more passengers and are therefore the more efficient option in terms of reducing pollution.

Cars are huge carbon contributors

Cars are a major contributor to carbon emissions. In the US, transportation is responsible for about 28% of total greenhouse gas emissions, making it the largest contributor to US GHG emissions. Similarly, in the EU, transport was responsible for about a quarter of the EU's total CO2 emissions in 2019, with passenger cars accounting for 61% of this.

A typical passenger vehicle emits about 4.6 metric tons of CO2 per year. This assumes the average gasoline vehicle has a fuel economy of about 22.2 miles per gallon and drives around 11,500 miles per year. Every gallon of gasoline burned creates about 8,887 grams of CO2. In addition to carbon dioxide, automobiles using gasoline produce methane, nitrous oxide, and hydrofluorocarbons from the tailpipe.

The impact of these emissions is significant. The buildup of carbon dioxide and other greenhouse gases is causing the Earth's atmosphere to warm, resulting in changes to the climate. While electric vehicles are gaining traction, with 17.8% of all new registered passenger vehicles in 2021 being electric, the majority of road transport vehicles in Europe still use diesel or petrol.

Switching from a solo commute by car to public transportation can significantly reduce an individual's carbon footprint. A single person who switches from a 20-mile solo commute by car to public transportation can reduce their annual CO2 emissions by 20 pounds per day, or more than 48,000 pounds in a year. This is equivalent to a 10% reduction in all greenhouse gases produced by a typical two-adult, two-car household.

Buses reduce traffic and idling cars

While buses emit more CO2 than cars, they are still a more sustainable and environmentally friendly mode of transportation. This is because buses reduce the number of cars on the road, which in turn reduces traffic congestion and the number of idling cars.

Idling cars are a significant source of vehicle emissions, contributing to air pollution and climate change. By taking cars off the road, buses help to reduce the amount of time vehicles spend idling in traffic, reducing vehicle emissions and improving local air quality.

Buses also offer a more fuel-efficient means of transportation. If five people drove their own cars on a 25-mile trip at 25 miles per gallon, they would collectively emit about five gallons of emissions. However, if those same people travelled by bus, they would only produce one gallon of emissions for the entire trip. This is because buses have better person-miles per gallon rates than single-occupant vehicles.

In addition to reducing emissions, buses offer several other benefits that contribute to a sustainable future. They provide a more affordable and reliable option for commuters, reducing the cost of transportation for individuals. Buses also allow passengers to rest during their commutes and are generally safer than travelling in personal vehicles, reducing the risk of fatal accidents.

To maximise the benefits of buses in reducing traffic and idling cars, several strategies can be implemented. These include infrastructure modifications, such as implementing roundabouts instead of four-way stops, to improve traffic flow and reduce unnecessary stops. Additionally, establishing idle reduction policies for buses, such as turning off engines during loading and unloading, can further decrease emissions and fuel costs.

Buses are more sustainable due to fuel efficiency

Buses are a more sustainable mode of transportation than cars due to their fuel efficiency. While buses emit more CO2, their fuel efficiency makes them a natural choice for sustainable living. If five people drove their cars 25 miles at about 25 miles per gallon, each person would emit about one gallon's worth of emissions. That's a total of five gallons of emissions. However, if those same five people took a bus, they would only use one gallon's worth of emissions for the entire trip. This reduces the gallons-per-person rate from one gallon per person to one-fifth of a gallon per person for the same trip. Each person has a lower carbon footprint because they have collectively used less fuel to travel, making buses more fuel-efficient than cars.

Buses also play a key role in reducing carbon emissions. Public transportation in the United States saves 37 million metric tons of carbon dioxide annually, equivalent to the emissions from the electricity used by nearly five million households. Buses reduce the amount of gas burned by up to 4.2 billion gallons per year, making them an affordable and reliable option for commuters.

Electric buses are also becoming more prevalent and offer environmental benefits. They produce no exhaust emissions, reducing greenhouse gas emissions, and are highly energy-efficient. Even in countries where energy production is based on fossil fuels, electric buses have a lower environmental impact than internal combustion engines.

While some sources argue that buses are less fuel-efficient due to their larger size and higher fuel consumption, this comparison assumes that buses are under capacity. Fuel efficiency for mass transit increases with population density, and buses provide an average of 7.61 more people per vehicle than cars. Thus, buses are more fuel-efficient than cars when considering the number of people transported.

Overall, buses are more sustainable than cars due to their fuel efficiency, reduced carbon emissions, and affordability. They offer a lower carbon footprint per person and contribute to a more sustainable future.

Frequently asked questions