Walking or cycling produces zero emissions and requires no fossil fuels, making it the most environmentally friendly mode of transportation.

Carbon dioxide (CO2) is the primary greenhouse gas emitted by transportation activities, accounting for over 70% of total emissions.

Road transportation, including cars, trucks, and buses, is the largest contributor to greenhouse gas emissions from transportation, accounting for over 70% of total emissions.

Induced demand refers to the phenomenon where the construction of new roads or the expansion of existing ones leads to an increase in traffic congestion and pollution, as more people are encouraged to drive.

Nitrogen oxides (NOx) are primarily responsible for smog formation, which is a type of air pollution characterized by a brownish haze.

Transportation activities, particularly road traffic, are the primary source of air pollution in urban areas, contributing to high levels of pollutants such as particulate matter, nitrogen oxides, and carbon monoxide.

Catalytic converters have been widely adopted in vehicles to reduce emissions by converting harmful pollutants into less harmful substances.

Transportation demand management (TDM) refers to the practice of reducing the number of vehicles on the road by encouraging the use of alternative transportation modes, such as public transportation, cycling, and walking.

Copenhagen is known for its extensive network of bike lanes and its promotion of cycling as a primary mode of transportation, with over 50% of residents commuting by bike.

Transportation externalities refer to the negative effects of transportation on the environment, such as air pollution, climate change, and habitat fragmentation, which are not reflected in the price of transportation.

The International Maritime Organization (IMO) has adopted regulations to reduce greenhouse gas emissions from international shipping, including measures to improve energy efficiency and reduce the carbon intensity of shipping operations.

Sustainable mobility refers to the shift towards more sustainable and environmentally friendly transportation systems, including the promotion of public transportation, cycling, walking, and the use of electric and fuel-efficient vehicles.

London has implemented a congestion pricing scheme, known as the London Congestion Charge, which charges drivers a fee for entering certain areas of the city during peak traffic hours.

Complete streets are designed to accommodate all users, including pedestrians, cyclists, and public transportation, making them more walkable and bikeable.

Electric vehicles, powered by electricity from renewable sources, have emerged as a promising alternative to traditional fossil fuel-powered vehicles, offering zero emissions and improved energy efficiency.