TIFFS: In future, more driving with fewer cars a possibility, researcher concludes

Number 13 in the Transport-in-a-Fine-Fix Series.

360px-CBX_Parkchester_6_jeh[1]Up till now, I have only looked at the numbers on American driving in the aggregate – total vehicle miles traveled (VMT) among all types of vehicles occupying U.S. roads. This has been both done for VMT for each person within the population (or per-capita) and total VMT. What about looking only at one facet of automobility: light-duty vehicles; i.e., cars, pickup trucks, sports utility vehicles and vans? Well, at least one individual has done just that. Why this was done will hopefully become clearer as this discussion develops.

Michael Sivak at the University of Michigan, through its Transportation Research Institute (TRI), has published a multipart study titled: “Has Motorization in the U.S. Peaked?” So, has U.S. automobility reached its maximum?

In part 1, “motorization” appears to relate to the number of vehicles in use, while in “Has Motorization in the U.S. Peaked? Part 2: Use of Light-Duty Vehicles,” this part seems to deal more with the driving aspect with some reference to the vehicle numbers that was brought out in part 1.

Before delving more deeply into the Sivak research, a couple of points made in my earlier postings:

First, per-capita vehicle miles traveled (VMT) hit a high in 2004, then trended negatively until bottoming out after which it saw a rebound, the positive growth commencing in year 2014 – per-capita VMT was 0.9 percent greater in 2014 than it was in 2013.

Next, total VMT peaked in 2007, then slid back some until 2012 when it too began to ramp back up.

Furthermore, in related reporting on this in “Air fare: Why top-heavy roadway spending makes little sense,” I wrote: “Chris McCahill at the State Smart Transportation Initiative (SSTI) states, ‘Unlike other past dips in driving, this recent downward shift has had no clear, lasting connection to economic trends or gas prices. Evidence suggests that the decline is likely due to changing demographics, saturated highways, and a rising preference for compact, mixed-use neighborhoods, which reduce the need for driving. Some key factors that pushed VMT upward for decades – including a growing workforce and rising automobile ownership – have also slowed considerably. SSTI released a report last September outlining the many contributing factors, with references to supporting literature.’”

That, obviously, is one person’s determination. Comparatively speaking, regarding the light-duty-vehicle (LDV) picture in a similar vein, what happened there?

Some of Sivak’s important findings:

  • Peak per-capita VMT for LDVs – 9,314 in 20041
  • Peak total VMT for LDVs – 2.773 trillion in 20062

Something else: Sivak in 2013 brought to bear how many vehicles there were in operation on American roadways then: roughly 253 million3 in the grand scheme of things. He also reported for year 2011 there were 233.8 million LDVs.4 Light-duty vehicles reached a maximum in the U.S., meanwhile, in 2008 with 236.4 million.5

Moreover, whereas with total LDV VMT, which peaked in 2006, it hit bottom in 2008 – just two years later, with 2.633 trillion miles registered.6 This compares with the aggregate (all vehicles) total VMT, which troughed in 2011 with 2.929 trillion VMT. Meanwhile, LDV VMT in 2011 was 2.647 trillion.7

As for per-capita total LDV VMT, like aggregate total per-capita VMT, both peaked in 2004. In the case of the former it was 9,314, while in the case of the latter or aggregate per-capita VMT in 2004, it exceeded 10,000. Meanwhile, aggregate average total per-capita VMT after edging down to a point right around 9,402 since ’04, it was there that this statistic more or less began leveling off until it again changed direction beginning in 2014.

The main takeaway I believe from at least this part of Sivak’s research, anyway, is this: the amount of light-duty vehicle driving in 2008, which had dipped to a post-peak low of 2.633 trillion miles of roadway travel recorded, was that in the exact same year more than 236.4 million LDVs occupied space on American roads (this, of course, prior to the full effect of the Great Recession being felt) – the highest, according to the University of Michigan TRI researcher, that is, up to and including year 2011 (the last year for which data was available for the “Has Motorization in the U.S. Peaked?” study).

So, what can one infer from all of this?

One possibility? A point Sivak brings to light in his research as I understand it, is that, in the future, LDV driving could tick up, and with a lower number of LDVs traveling American roadways to boot.8

Why is this important? On matters of air quality, such could be telling, indeed.


  1. Michael Sivak, “Has Motorization in the U.S. Peaked? Part 2: Use of Light-Duty Vehicles,” University of Michigan, Transportation Research Institute, Report No. UMTRI-2013-20, July 2013, p. 9
  2. Ibid, pp. 5 & 6
  3. Michael Sivak, “Has Motorization in the U.S. Peaked?,” University of Michigan, Transportation Research Institute, Report No. UMTRI-2013-17, June 2013, p. 1
  4. Ibid, pp. 3 & 4
  5. Ibid
  6. “Has Motorization in the U.S. Peaked? Part 2: Use of Light-Duty Vehicles,” University of Michigan, Transportation Research Institute, Report No. UMTRI-2013-20, July 2013, p. 6
  7. Ibid, pp. 5 & 6
  8. Ibid, p. 14

1 thought on “TIFFS: In future, more driving with fewer cars a possibility, researcher concludes”

  1. The car should be emptied completely of all perxonal belongings and documents before giving it for shipping.

    Roosevelt that authorized a network of rural and urban express highways, dubbed
    the “National System of Interstate Highways. Putting them into someone’s care is an act of faith.

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