"Cooperation in the transport sector has been at the core of the Greater Mekong Subregion (GMS) Economic Cooperation Program (hereinafter GMS Program) since its inception in 1992. The main thrust of the GMS Program was eliminating the barriers to cooperation. The significant lack of connectivity was a critical constraint on economic relations among the GMS countries. The initial effort to pursue a coordinated approach to establishing links and developing the transport sector in the GMS was made in 1994 through the Subregional Transport Sector Study for the Greater Mekong Subregion (hereinafter GMS Transport Sector Study), which examined the (i) most important links that need to be established, (ii) most suitable modes for such links, (iii) criteria for prioritizing system elements, and (iv) possible phasing of development.1 The GMS Transport Sector Study identified a set of subregional transport projects covering road, rail, water, and air transport. It guided GMS transport cooperation during 1994– 2005, with the list of projects being updated and refined over time. The priority projects in the GMS Transport Sector Study became the backbone of the GMS East–West Economic Corridor (EWEC), the North–South Economic Corridor (NSEC), and the Southern Economic Corridor (SEC) when the GMS countries adopted the economic corridor concept in 1998. They also constituted the first set of GMS transport projects—e.g., the Phnom Penh–Ho Chi Minh City Highway, the East–West Corridor Project, and the Northern Economic Corridor (Boten– Houayxay) Project—that were implemented under the GMS Program. As these projects neared completion, the need to address policy and regulatory issues involving the movement of people and goods across borders became urgent. The GMS Cross-Border Transport Facilitation Agreement (CBTA) was thus initiated in 1999 to complement hardware with software of connectivity in the GMS..."