The value of freight movements between the U.S. and its two next door neighbors moved back into negative territory following the first year-over-year increase since late 2014.

New U.S. Transportation Department figures show only the transportation modes of rail and air carried more U.S. freight by value with North American Free Trade Agreement (NAFTA) partners Canada and Mexico in September compared the same time a year earlier as total freight on all modes decreased 2.3% to $91.1 billion.

The total value of cross-border freight has declined from the same month of the previous year in 20 of the past 21 months beginning in January 2015 with only an increase of 0.7% this past August.

The value of commodities moving by rail and air increased 8% and 3.4% respectively, while the value of freight carried on other modes decreased: truck, 3.8%; pipeline, 5.2% and vessel, 6.8%.

Despite this drop, trucks carried 64.7% of U.S.-NAFTA freight and continued to be the most heavily utilized mode for moving goods to and from both U.S.-NAFTA partners. Trucks accounted for $30.1 billion of the $48.8 billion of imports, or 61.7%, and $28.9 billion of the $42.4 billion of exports, or 68.1%.

Rail remained the second largest mode by value, moving 15.9% of all U.S.-NAFTA freight. The surface transportation modes of truck, rail and pipeline carried 85.5% of the total value of U.S.-NAFTA freight flows.

Canada Freight Value Falls 4.4%

The value of U.S.-Canada freight flows fell 4.4% to $46.2 billion in September compared to the same time in 2015 mainly due to decreases in the value of goods moved by vessel and pipeline. All modes of transportation except rail carried a lower value of U.S.-Canada freight than a year earlier.

The top commodity category transported between the U.S. and Canada by all modes was vehicles and parts, of which $5.2 billion, or 55.9%, moved by truck and $3.9 billion, or 41.8%, moved by rail.

Trucks carried 59.6% of the value of the freight to and from Canada. Rail carried 16.4% followed by pipeline, 9.0%; air, 5.1%; and vessel, 2.9%. The surface transportation modes of truck, rail and pipeline carried 85.0% of the value of total U.S.-Canada freight flows.

Mexico Freight Value Nearly Unchanged, Despite Truck Downturn

To the south, from September 2015 to September 2016, the value of U.S.-Mexico freight decreased 0.04% to $44.9 billion despite four modes of transportation – pipeline, rail, air, and vessel – carrying a higher value of U.S.-Mexico freight than a year earlier.

Truck, which account for 69.9% of the value of freight to and from Mexico, was down 4%. Freight carried by pipeline increased by 15.3%, rail by 12.9%, air by 10.9%, and vessel by 7.1%.

The top commodity category transported between the U.S. and Mexico by all modes in September 2016 was electrical machinery, of which $7.4 billion, or 81.8%, moved by truck.

Rail carried 15.4% of the value of freight to and from Mexico followed by vessel, 7.9%; air, 3.1%; and pipeline, 0.8%. The surface transportation modes of truck, rail and pipeline carried 86.1% of the value of total U.S.-Mexico freight flows.