Are Detroit's growing traffic jams a good economic indicator?

Gridlock is down in the U.S. overall but up in metro Detroit, and the traffic pundits say this may be a good sign.

Excerpt:

"INRIX, a company that measures traffic flows around the world, says its "INRIX Gridlock Index" of traffic congestion for major U.S. cities declined in December by 2.9% from a year earlier...

However..."INRIX notes that 'Detroit, the traditional IGI underperformer, defied the expected seasonal effect which normally sees traffic fall from November to December. Detroit's gridlock increased by almost 10 percent month-over-month; by contrast the IGI composite for all 10 metropolitan areas fell by approximately 14 percent. This may be a positive signal for Detroit's economy.'"

More here.