transportation and trade weight trends of manufactured goods and non-ferrous metals between europe, asia and africa

this research aims to study the trade weight trends of manufactured goods and non-ferrous metals, respectively identified by codes 6 and 68 in the standard international trade classification (sitc), for 125 countries throughout asia, europe and africa in 9 distinct years spanning a 40-year time period between1965  and 2005. four sets of variables were implemented to construct the trade gravity models, gross domestic product and three transportation parameters representing three types of transportation networks. the derived gravity models revealed the trends of trade and transportation for the two subject trade items. these trends suggest that trade weight sensitivity with respect to transportation factors has grown for both commodities throughout the time period. moreover, a trend comparison between the head section, code 6, and one of its divisions, code 68, is made possible.