Isn't this confusing the issue? Traffic Congestion isn't traffic volume. One huge factor could easily be weather in which we've had some of the worst weather in a few years. Which ruins roads and congests traffic. They're looking at this as "How difficult it takes to get to work" as an indicator of our GDP? just because they lined up for a year or 2 doesn't make a correlation... Other factors (+/-): Working from home, bad roads, increase in jobs, older cars on the road, more accidents.