Decline in economic activity and congestion in Greater Washington

The report "Washington region's fabled traffic jams eased a little last year" (Washington Post) which reports that Inrix, a traffic data analysis firm, found a decline in traffic congestion in Greater Washington in 2013.

Using automobile data about freeways misrepresents the complete mobility picture.  It illustrates the point that I make frequently, that studies of congestion focus on freeways, and thus over-state the amount of "congestion" in urban areas with strong transit systems and a compact urban form with a mixed use land use paradigm. 

That is the case with the current report, according to the Post graphic accompanying the article, which lists 9 different freeway/parkway segments as among the 200 most congested roadways in the U.S.

DC is not Metropolitan Washington and has a significantly different transportation system than the freeway-dominated suburbs.  While there is a great deal of "congestion" in the suburbs, for people who do not rely on automobility, DC proper is not terribly congested, although there is no question that the roads serving primarily as commuterways in and out of the city are an exception.

Reports at the time didn't find a significant drop in automobile congestion during the shutdown.  However, the report stating that congestion in the greater metropolitan area was down in 2013 because of the government shutdown contradicts reporting at the time ("Federal workers off, traffic isn't," Post) which found that traffic didn't vary much, although there was a decrease.

A majority of people working downtown use transit.  It is suggested that this was the case because a majority of government workers use transit to get to work, automobile-based traffic wasn't significantly impacted.  I seem to recall that about 65% of the people working in "Downtown DC" use transit.

From the article:

Thousands of furloughed federal workers are free to sleep in again this week, but the perpetual nightmare of congested traffic continues to haunt the Washington region.

Traffic on the main roads in and around the District has dropped by 5 percent or less during the morning rush hour, according to traffic analysts. It’s held steady or bumped up slightly at midday, with the only real decline — between 10 and 30 percent — coming during the evening trip home. ...

“There’s just a whole lot of people working in this region who are not federal employees. They’re still out there,” he said. “And federal workers are disproportionately higher users of transit. A much smaller percentage of them drive than the region as a whole.”

Graphic depicting the Inrix traffic prediction model from the Gigaom article "Why better traffic data means more than just a faster commute."

Inrix only measures automobile activity, which skews what it reports.  One of the problems relying on a traffic-GPS system for cars on generalizing mobility within an area like Greater Washington is that it only measures automobility, so that its usefulness should be called into question because by definition it doesn't measure other modes.  From the first cited article:

Much has been written about a shift in the region’s urban dynamic, with people who once fled the city or who grew up in suburbia moving to the District. The population is up, but the number of households that own a car and the number of licensed drivers are not. More people are using public transit, rental cars and bicycles to get around town.

But that’s not unique to Washington, nor is it the primary reason that the region saw a decline in congestion.  “That’s what happens when D.C. shuts down for a month and government hiring slows with sequester,” said Jim Bak of Inrix.

Reduced economic activity does lead to reduced automobile use and reductions in congestion.  In any case, it is a good point that a decline in federal economic activity will impact automobile use and rush period traffic, contributing to congestion reduction.