Transportation costs for US imports from developed and developing countries
研究了1981年美国进口的国际运输成本及1976至1981年的变化，发现发展中国家面临更高的运输成本负担，且最不发达国家的劣势在加剧。
This study measures international transportation costs for US imports in 1981 and changes in these costs from 1976 to 1981. It then examines how the levels and the changes in these costs vary with the level of development of the import‐supplying country. Transportation costs continue to be a significant barrier to US imports, but relative transportation costs have declined sharply in recent years. The ratio of transportation costs to value is greater for US imports from developing countries than for US imports from developed countries and is greatest for US imports from least developed developing countries. Furthermore, the transportation cost disadvantage of least developed developing countries has been increasing.