ABSTRACT

The expansion of production of non-traditional crops at rates, especially in the semi-arid areas of north-east Thailand, was associated with considerable road development and new road construction. Economic development had been based on rice production in the central plains where water transport was available, cheap and convenient. In 1980 the two principal agencies responsible for highway and road construction in Thailand were the Department of Highways of the Ministry of Communications and the Office of Accelerated Rural Development of the Ministry of Interior. Stage construction of road projects has been an element in network planning and improvement for many decades. No evaluation of the economic effects of highway construction and improvement projects in Thailand could be considered worthy without reference to the monumental work of the late Sei-Young Park, senior transportation economist of the World Bank. The Department of Highways conducts systematic traffic counts separately for national highways and provincial highways.