The environmental stress generated by urbanization has many interrelated causes. Some of these stresses are manifested as a result of increased vehicular traffic in urban areas. These cause traffic jams, leading to air pollution, problems in personal health, loss of productive labour time, and economic losses. Average travel speed in the center of Bangkok, during peak hours, is about 12 kms/hr! To this situation, 400 to 600 vehicles are added to its streets everyday.

The following chart, taken from a WRI Report, illustrates the link between economic losses and traffic congestions in key South-East Asian cities.

Source: World Resources Institute, World Resources 1996-97, 1997.