Thoughts on 7th Annual INRIX Traffic Scorecard Report
“Travel times are declining in the U.S.,” he said. “People are aging. Old people don’t travel as much, and young people don’t travel as much as what young people used to. Fewer kids own cars. The big picture is that that the total amount of travel peaked in the U.S. a few years ago and it’s been declining ever since. We have some ups and downs during any given year depending on the price of the gas and whether the economy is doing a little bit better or not. Certainly [congestion is] more than in 2009 during the depths of the recession.”
I agree with David’s assessment.
INRIX’s report is claiming that traffic congestion is increasing and that trend is tied to the improving economy. I don’t disagree that we’re seeing a slight shift, but I think the above chart from the Traffic Scorecard illustrates that we’re seeing just a slight upturn in the last two months of 2013 in the U.S. It might be more illustrative to lay out this monthly data from January 2010 sequentially through December 2013 (not stacking years on top of each other). Then you’d see congestion was steadily dropping from January 2010 until December 2011 and then it plateaued in a trough from January 2012 until November 2013.
I’m still going to be cautious about preparing long term traffic forecasts. This blip in congestion may show the start of increasing traffic congestion and vehicle miles traveled (VMT), but we’ll need a couple of years of VMT data before we go back to trendlining forward significant traffic growth rates. I’m with David – demographics are against a surge in VMT.
I found the chart below to be useful. To me it affirms that we should look to Tuesday, Wednesday or Thursday for “normal” baseline traffic counts. The morning traffic is very much the same on each of those days, but there is a spread in the afternoon traffic. If we’re looking to capture “normal – normal” traffic conditions, maybe we should only do counts on Wednesdays. If we want the “peak of normal,” maybe we should only do counts on Wednesdays.
I’m still going to stick with claiming Tuesday/Wednesday/Thursday all qualify as “normal” traffic conditions for roadway design purposes, but I’m not sure if one day is better than another if you’re updating signal timing plans.