By David Alpert, June 8, 2015
When Virginia chooses transportation projects, should it narrowly look only at what makes cars move faster? Or should it consider how each project will transform the region, and pick the ones that do the most for residents, the economy, safety, and quality of life? A state board will soon tip the scales one way or the other.
A state board is soon going to decide how to weigh reducing congestion against other factors like economic development, making jobs more accessible, or even safety. How much of a priority goes to congestion will affect the way Northern Virginia grows in coming decades.
What's wrong with focusing on congestion reduction
While nobody likes congestion, putting all money into making cars move faster is foolish. As I wrote in 2011:
Consider two hypothetical cities. In Denseopolis, people live within 2 miles of work on average, but the roads are fairly clogged and drivers can only go about 20 miles per hour. However, it only takes an average of 6 minutes to get to work, which isn't bad.
On the other hand, in Sprawlville, people live about 30 miles from work on average, but there are lots and lots of fast-moving freeways, so people can drive 60 mph. That means it takes 30 minutes to get to work.
Which city is more congested? ... Denseopolis. But it's the people of Sprawlville who spend more time commuting, and thus have less time to be with their families and for recreation.This graph shows how focusing on congestion can point in the wrong direction: Chicago drivers waste more time in traffic than Charlotte drivers, but Charlotte drivers have worse commutes. Yet a congestion-only standard says that Chicago has the worse problem.
Graphic from CEOs for Cities.
Induced demand means congestion won't go away at all
Plus, even the kind of spending the road advocates want won't cut down on congestion for most people. That's because even though they have improved, traffic models still undercount the extent a newly faster road will just entice people to move somewhere that requires driving on it, adding traffic back in. That effect is called "induced demand."
Jeff Speck's excellent book Walkable City gives a terrific explanation of the induced demand problem:
Induced demand is the great intellectual black hole in city planning, the one professional certainty that everyone thoughtful seems to acknowledge, yet almost no one is willing to act upon. It's as if, despite all of our advances, this one (unfortunately central) aspect of how we make our cities has been entrusted to the Flat Earth Society. ...
Induced demand is the name for what happens when increasing the supply of roadways lowers the time cost of driving, causing more people to drive, and obliterating any reductions in congestion. In 2004, a meta-analysis of dozens of previous studies found that "on average, a 10 percent increase in lane miles induces an immediate 4 percent increase in vehicle miles traveled, which climbs to 10 percent—
the entire new capacity— in a few years."
The most comprehensive effort remains the one completed in 1998 by the Surface Transportation Policy Project, which looked at fully 70 different metropolitan areas over 15 years. This study, which based its findings on data from the annual reports of the conservative Texas Transportation Institute, concluded as follows:
"Metro areas that invested heavily in road capacity expansion fared no better in easing congestion than metro areas that did not. Trends in congestion show that areas that exhibited greater growth in lane capacity spent roughly $22 billion more on road construction than those that didn't, yet ended up with slightly higher congestion costs per person, wasted fuel, and travel delay. ... The metro area with the highest estimated road building cost was Nashville, Tennessee with a price tag of $3,243 per family per year."The computer models that predict congestion do not consider pedestrians, for instance, even though getting more people to walk has reduced traffic in places like the Rosslyn-Ballston corridor in Arlington. Theoretically, a much more sophisticated model could understand the congestion reducing effects of walkability and the congestion-increasing effects of induced demand, but today's models don't do this well enough.
Nobody likes congestion, and, despite appearances, I am not arguing here for more of it. Rather, I am asking that it be better understood by those who build and rebuild our communities, so that we can stop making stupid decisions that placate angry citizens while only hurting them in the long run.
What happened with HB2, and why is this an issue now?
Thanks to education and advocacy, the Virginia legislature amended HB2 to not focus solely on congestion. Instead, the statewide Commonwealth Transportation Board has to devise a scoring system which balances "congestion mitigation, economic development, accessibility, safety, environmental quality and land use, and transportation coordination."
In 2015, the congestion crowd, led by Fairfax and Loudoun Rep. Jim LeMunyon (R), pushed another bill to force Northern Virginia specifically to prioritize congestion reduction "to the greatest extent possible and in the most rapid and cost-effective manner."
The CTB will soon propose weights for these various factors, and that's where the fight is.
Road booster groups like the Northern Virginia Transportation Alliance (no relation to the Northern Virginia Transportation Authority) don't like 35%. Even though that gets the biggest weight, NVTA wants it to get overwhelming weight—
NVTA is asking members to email Six-YearProgram@VDOT.Virginia.gov to ask to weight congestion more highly. If you live in Virginia, instead consider emailing them to support keeping the weight at 35% or, if possible, making it even less.