The flow of trucks and rail containers across the U.S. Mexico border is growing, but not at a tremendously fast pace according to data from the U.S. Department of Transportation Bureau of Transportation Statistics. In 2014, 3.8 million loaded truck containers and 474k loaded rail containers crossed the U.S.-Mexico border including northbound and southbound flows. That means there were 8 truck crossings for every one rail container crossing in 2014, and the ratio has been 10:1 or more in some years, including 2009 and 2010. The compound annual growth rate from 1996 to 2014 was 4.5% for truck and 6.9% for rail.
The annual percentage growth or decline in rail container crossings is much more volatile than truck crossings, growing faster when the economy is strong but shrinking more when the economy is weak (and when rail service is challenged). Trucking companies reduce prices in weak economies to hang on to freight and keep their trucks moving. In stronger economies trucking companies take price increases to improve financial results when there is a shortage of equipment. Rail picks up the slack. The annual numbers show that there is only one year since 1999 that truck crossings have grown by more than 10% year-over-year, while rail growth has exceeded 10% in 7 of these years. In 2014, it is likely that industry-wide rail service and capacity issues prevented rail from continuing to grow at a faster rate than truck for U.S.-Mexico trade.
It is also clear that cross-border trucking has become more balanced between northbound and southbound flows, while rail container crossings remain highly imbalanced. In the late 90’s there was almost one empty truck border crossing for every loaded truck crossing. In 2014, 71% of all truck crossings were loaded. Given that there is more northbound than southbound freight, there are probably relatively few northbound empty crossings so the numbers imply that there is still about 1 empty for every 1 loaded southbound truck move. Rail crossings remain highly imbalanced and only in the last 2 years have there been more loaded than empty rail container crossings. Again, given the stronger northbound flows, the number suggest that there are very few southbound loaded rail container moves. The dramatic difference in equipment balance between truck and rail reduces the overall economic advantage of rail versus truck because of the need to move empties southbound to handle the northbound flows. Despite this inefficiency, intermodal is growing at a faster pace than truck driven by the long haul nature of cross-border freight, the shortage of long haul truck drivers, customs clearance advantages, and the overall economic advantage of rail over truck for long haul transportation.