If the transportation industry is any indicator — and it usually is — then the economy could be on the brink of a downturn.
When the economy is on the decline, the transportation sector is one of the first things to go. According to a report by the U.S. Bureau of Transportation Statistics, shifts in its index that tracks train, truck, boat and plane activity occur before changes in economic growth, leading the wider economy by about four months.
The index has taken a negative turn starting in late 2015 and into the summer of 2016, according to CNBC calculations. While true turning points are usually identified after the fact, the recent downward momentum could signal a similar movement in the economy as a whole.