According to INRIX, traffic in the U.S. reversed two consecutive years of declines with a six percent increase in 2013. The country's GDP, by comparison, grew 1.9 percent last year. INRIX suggests that continued economic growth will result in more traffic congestion, longer commutes, and more productivity losses.
INRIX is getting their conclusion from one data point: last year. Even though previous years do not support their conclusion, multiple data points. As a result, their conclusion that traffic increases at 3 times GDP growth is not convincing. They need to put a lot more effort into this study. Even the article author pointed that out,
Bottom line: roadways are complex ecosystems, and congestion results from jobs, commuters, road work, mass transit, and countless other factors. While it's encouraging to see traffic jams as symbolic of economic growth, that's not an accurate or complete picture.
In a complex environment like this, data needs a control point and a link from cause to effect. All I see here is a very loose correlation in one year of data. Hence, this is FUD.