Since human beings transformed their lifestyles from hunter gathering to an agricultural and domesticated existence, they have searched for ways to move around other than on foot. Early forms of transport included boats and horses. It was not until the Industrial Revolution however, that transport really took off, with the development of steam power and the train in the 18th and 19th centuries, and the combustion engine and road transport in the 20th century. The use of fossil fuels to power transport made long-distance travel much more accessible.
Most forms of transport involve the combustion of fossil fuels, which adds to the problem of air pollution. Air pollution problems are most intense where the traffic is most dense, around city centres and airports, for example. Over the years, as transport has been used more widely, legislation has been introduced to reduce the amounts of pollutants released, and in modern society vehicles are becoming increasingly environmentally friendly. However, this positive effect is offset by the increasing number of vehicles. For example, in the UK, experts predict that car traffic will grow by at least 50% over the next 25 years.
In addition to the pollution issues, traffic (especially road traffic) and associated construction work also contributes to issues such as congestion, noise pollution and the disruption of ecosystems