Methodology to Obtain a Mexico–U.S. Multiproduct Origin–Destination Matrix

In the Mexican Transportation Institute, multiproduct truck traffic assignment models have been developed over the past 15 years to assess improvements to the infrastructure and the transborder transport services between Mexico and the United States. A basic input of those models is the multiproduct (by product type) origin–destination (O-D) matrix. A better prediction of flows from the assignment models is obtained if the O-D matrix input contains the flows from the origin states in Mexico, toward the border crossings, and from these to the destination states in the United States for the Mexican exports and vice versa for the Mexican imports. To obtain this matrix, the information of transborder crossings of the U.S. Bureau of Transportation Statistics (BTS) is combined with O-D information that has been gathered in Mexico for more than 15 years from field stations installed in different places of the Federal Road Network. A two-step procedure is used to combine the two previous sources (a) to escalate the Mexican flows so that what arrives at each border site (Mexican information) equals what leaves that border site toward each state of the United States (BTS Database 11) and (b) to use a gravitational procedure to distribute what arrives at the border sites for a certain product type (Mexican information) in what arrives at each state of the United States of that product type (BTS Database 9). A similar methodology has been applied for the imports from the United States.