Trade using surface transportation between the United States and its North American Free Trade Agreement partners Canada and Mexico was 39.5 percent higher in May than in May 2009, reaching $66.8 billion, according to the Bureau of Transportation Statistics of the U.S. Department of Transportation.

The increase was the largest percentage year-over-year increase in total U.S.-NAFTA trade by surface modes on record back to April 1994. May was the third month in the last four with a record percentage year-over-year increase.

BTS reported the value of U.S. surface transportation trade with Canada and Mexico in May remained 9.9 percent below the May 2008 level. North American surface freight value rose 1.5 percent in May 2010 from April. Month-to-month changes can be affected by seasonal variations and other factors.

U.S.–Canada surface transportation trade totaled $40.2 billion in May, up 37.5 percent from May 2009. U.S.–Mexico surface transportation trade totaled $26.6 billion in May, up 42.7 percent from May 2009.

Surface transportation consists largely of freight movements by truck, rail and pipeline. In May, 86.2 percent of U.S. trade by value with Canada and Mexico moved on land.