During the last quarter of a century there has been a significant increase in the proportion of journeys travelled by car and the distance that people travel. Associated with these rising figures has been an increase in the pressures due to transport placed upon the environment and society. These pressures have increased not just in the UK but also worldwide.
Congestion in cities is acknowledged as a major problem throughout the world. No large city seems to have escaped peak period congestion. It is a problem in countries with generous road systems and low resident densities like the United States, as well as in countries like Turkey and Poland, with relatively low levels of car ownership, but poor road infrastructure. Rising volumes of road traffic and increased congestion have caused a decrease in the efficiency of delivery services that depend on transport, and a subsequent increase in transportation costs due to increased journey times.
Transport is becoming an increasing source of air pollution. The transport related problems experienced now are likely to worsen according to the projected increase in traffic. The motor vehicle engine emits many types of pollutants including nitrogen oxides, carbon monoxide, particulates, sulphur dioxide, lead (in some cases) and the greenhouse gas carbon dioxide. Individually, a vehicle engine is not a particularly important source of pollution. Collectively however, vehicles represent a major source of air pollution in the UK and throughout the world. Impacts of transport on the environment include acid rain, human health effects, global warming and noise pollution. The best way to reduce the threat of air pollution is to use cleaner fuel and less of it, and to adopt more sustainable modes of transport like public transport, walking and cycling.