Thailand is setting out plans for a major development of its transport network. The country’s government has been discussing plans for five special economic zones, as well as the new transport links that will connect these areas. The five special economic zones have been proposed in Trat, Tak, Songkhla, Mukdahan and Aranyaprathet. For Songkhla's Padang Besar and Sadao customs checkpoints, a 64km highway project costing some US$743.85 million is being considered that will run from the Malaysian border in Sadao district to Hat Yai. For Tak's Mae Sot customs checkpoint, renovation works will be carried out for the 46.6km Tanaosri-Kokarek road, while a 25.5km section and a 13.25km section of Tak-Mae Sot road will be expanded to four lanes. A 22km highway will be built to connect the Sa Kaeo Aranyaprathet customs checkpoint between 2016 and 2018. Other planned projects include the expansion of a section of Kalasin-Nakhai-Kham Cha-i road to four lanes and the widening of a section of the Kalasin-Somdej road.