Look up as you drive through Bangkok and town skyline tells the story before any road sign does. Concrete pillars rise from the sidewalks. Highways hover over highways. In some sections, three layers of road are stacked on top of one another.
Bangkok is home to one in all the densest networks of elevated expressways in Southeast Asia, including the Bang Na Expressway, a 54-kilometer elevated toll road recognized by the Guinness Book of Records because the longest road bridge on Earth.
And the entire story began when there was no space in town.
A city that grew faster than its path
Bangkok’s economic transformation began to speed up within the Nineteen Sixties. The Thai government launched its first National Economic and Social Development Plan in 1961, attracting large amounts of foreign investment to the capital.
The result was rapid urbanization. Bangkok’s population grew from about a million in 1950 to over three million in 1970, driven by continued migration from rural provinces.
As town developed, the extent of automobile ownership also increased. Government policy from the Nineteen Sixties onward prioritized automobile infrastructure, directing resources to road paving, bridge construction, and highway expansion. However, Bangkok had a structural problem that road expansion alone couldn’t solve.
Only eight percent of Bangkok’s total area consisted of roads, well below the 20–30 percent typical of most Western cities. In the dense urban core, where land was expensive and communities already occupied a lot of the available space, horizontal expansion had hard limits.
By the top of the Seventies, town had already gained the repute of a “road disaster city”. The variety of cars was always increasing. Road capability didn’t sustain with the changes. The difference between them caused a stalemate that worsened yr by yr until the Nineteen Eighties.
The decision to go vertical
Planning for elevated highways in Bangkok dates back to the Greater Bangkok Plan of 1960. The institutional framework was established on November 27, 1972, when the federal government established the Expressways Authority of Thailand (EXAT) as a state-owned enterprise under the Ministry of Transport.
EXAT’s task was to construct high-capacity controlled access highways over town’s existing street grid. Construction of the primary expressway in Thailand began in 1978.
The total investment in the primary stage reached 8.51 billion baht, with financial support from the Thai government and the Japan International Cooperation Agency (JICA).
The first section connecting Din Daeng with Tha Ruea was opened on October 29, 1981. The logic was easy: if land at ground level was too scarce and too expensive, the answer was to construct above it.
A scale that has grown over the many years
The network didn’t stop on the primary expressway. In 1983, a non-public company, Bangkok Expressway Public Company Limited (BECL), was established to further expand capability through public-private partnerships with EXAT.
Under the Build Transfer Operate concession, EXAT handled the land acquisition, while BECL managed the design, construction and operation. The first toll collection under this arrangement began in August 1987.
By 2015, EXAT managed seven expressways and 4 connecting routes with a length of 207.9 km. As of 2024, this has increased to eight major expressways and 4 connections with a length of 224.6 km, and 11 additional projects price 273.29 billion baht are within the pipeline.
The most visible product of this expansion was the Bang Na Expressway, which opened in February 2000. Built at a price of over a billion dollars and constructed using 1.8 million cubic meters of concrete.
Its 54-kilometer, six-lane road runs directly over national road No. 34, built on top of the highway.
Numbers beyond the horizon
The expressway sections operated by BEM alone cover a complete of over 100 kilometers of roadway, creating what BEM describes as one in all the densest toll expressway systems in Southeast Asia.
Thailand also has probably the most extensive road transport network in Southeast Asia, covering over 390,000 kilometers of roads throughout the country.
Bangkok’s elevated expressways are a physical record of a city that was growing faster than its land could accommodate, and the engineering response that followed.
