Health and environmental effects of transport

The health and environmental impact of transport is significant because transport burns most of the world's petroleum. This causes illness and deaths from air pollution, including nitrous oxides and particulates, and is a significant cause of climate change through emission of carbon dioxide. Within the transport sector, road transport is the largest contributor to climate change.

Environmental regulations in developed countries have reduced the individual vehicle's emission. However, this has been offset by an increase in the number of vehicles, and increased use of each vehicle (an effect known as the Jevons paradox). Some pathways to reduce the carbon emissions of road vehicles have been considerably studied. Energy use and emissions vary largely between modes, causing environmentalists to call for a transition from air and road to rail and human-powered transport, and increase transport electrification and energy efficiency.

Other environmental impacts of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands. By reducing transport emissions globally, it is predicted that there will be significant positive effects on Earth's air quality, acid rain, smog, and climate change. Health effects of transport include noise pollution and carbon monoxide emissions.

While electric cars are being built to cut down CO₂ emission at the point of use, an approach that is becoming popular among cities worldwide is to prioritize public transport, bicycles, and pedestrian movement. Redirecting vehicle movement to create 20-minute neighbourhoods that promotes exercise while greatly reducing vehicle dependency and pollution. Some policies include levying a congestion charge on cars travelling within congested areas during rush hour.

The most important impacts of transportation involve several dimensions: climate change, air quality, noise, water quality, soil quality, biodiversity, and land take.

The transportation sector is a major source of greenhouse gas emissions (GHGs) globally. An estimated 30 percent of national GHGs are directly attributable to transportation—and in some regions, the proportion is even higher. According to the International Energy Agency (IEA), the transportation sector accounts for more than one-third of CO₂ emissions globally.

Transportation methods are the greatest contributing source of GHGs in the U.S., accounting for 47 percent of the net increase in total U.S. emissions since 1990.

Other environmental effects of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands. By reducing transportation emissions globally, it is predicted that there will be significant positive effects on Earth's air quality, acid rain, smog and climate change.