Vehicle Miles Traveled: Where the Action Is

Where Vehicle Miles Traveled has increased the most, 2002 to 2015, as shown on this map of VDOT's transportation districts.

Where Vehicle Miles Traveled has increased the most, 2002 to 2015, as shown on this map of VDOT’s transportation districts.

A few days ago I published a graph showing that Virginia has experienced a modest increase in Vehicle Miles Traveled (VMT) since 2002, but I couldn’t draw any meaningful conclusions. Statewide numbers obscure the traffic dynamics in different parts of the state, and I didn’t have the time to drill deeper.

Inspired no doubt by my sparkling prose, Carol Bova took the trouble to compile the VMT numbers broken down by Virginia Department of Transportation (VDOT)’s nine transportation districts between 2002 and 2015. As the beneficiary of her exertions, I no longer have any excuses.

The data make it very clear: While Virginia roads and highways are getting more congested overall, some are getting congested faster than others. Indeed, some parts of the state are de-congesting (if that’s a word). This should come as no surprise to anyone familiar with Virginia’s demographic trends. The districts with stagnant VMT are experiencing stagnant or shrinking populations.

The overwhelming increase in VMT occurred in the  yellow oval in the map above. Other than an anomalous jump in Interstate traffic in the Staunton district — either Interstate 81 is getting very busy or Northern Virginia’s Interstate 66 commuter shed has leaped over the Blue Ridge Mountains — the overwhelming majority of the traffic growth occurred in just four districts: Northern Virginia, Richmond, Fredericksburg and Culpeper. Those four districts saw an increase of 13.2 million Vehicle Miles Traveled over the 13-year period — four times more than the 3.1 million increase for the other five districts combined.

Even this conclusion cries out for more granularity. The growth in VMT was almost assuredly more concentrated than a glance at transportation districts alone would show. The growth in the Richmond district occurred mainly in the Richmond metro area, not the rural expanse to the south. Likewise, growth in Culpeper and Fredericksburg assuredly took place in the counties in the growth path of metropolitan Washington. (Charlottesville might have added a small kicker for the Culpeper region.)

For all the region’s traffic bottlenecks, the percentage VMT growth in Hampton Roads was modest — on a par with Roanoke/Salem, a less populated transportation district. The Lynchburg district tread water, while the Bristol district lost traffic.

As an aperitif, here is a breakdown of the Vehicle Miles Traveled in absolute numbers (not percentage growth) broken down by transportation district in 2015. While traffic volume may be increasing the fastest in the Culpeper/Fredericksburg exurbs, the districts representing the three main metros — and that includes Hampton Roads — still predominate.

VDOT data exists to drill down locality by locality to confirm or rebut my tentative conclusions. If I ever have the time, I will compare 2002 and 2015 VMT for each Virginia locality and map the percentage increase with Exel’s cool new data mapping software (assuming I can figure out how it works). But don’t hold your breath. My sponsors keep me busy with energy and higher-ed.