The city has since turned to public transport in an attempt to solve this major problem.Five rapid transit lines are now in operation, with more systems under construction or planned by the national government and the Bangkok Metropolitan Administration.
Over 14 million people (22.2 percent) lived within the surrounding Bangkok Metropolitan Region at the 2010 census, making Bangkok an extreme primate city, significantly dwarfing Thailand's other urban centres in terms of importance.Bangkok traces its roots to a small trading post during the Ayutthaya Kingdom in the 15th century, which eventually grew and became the site of two capital cities: Thonburi in 1768 and Rattanakosin in 1782.Bangkok's rapid growth amidst little urban planning and regulation has resulted in a haphazard cityscape and inadequate infrastructure systems.Limited roads, despite an extensive expressway network, together with substantial private car usage, have led to chronic and crippling traffic congestion, which caused severe air pollution in the 1990s.The city is now a major regional force in finance and business.
It is an international hub for transport and health care, and has emerged as a regional centre for the arts, fashion and entertainment.
The city grew rapidly during the 1960s through the 1980s and now exerts a significant impact on Thailand's politics, economy, education, media and modern society.
The Asian investment boom in the 1980s and 1990s led many multinational corporations to locate their regional headquarters in Bangkok.
Bangkok became the centre stage for power struggles between the military and political elite as the country abolished absolute monarchy in 1932.
It was subject to Japanese occupation and Allied bombing during World War II, but rapidly grew in the post-war period as a result of United States developmental aid and government-sponsored investment.
The City Pillar was erected on 21 April, which is regarded as the date of foundation of the present city.