ANN ARBOR, Michigan — America's reliance on the automobile may be in a downward spiral, according to a new study from Dr. Michael Sivak of the University of Michigan Transportation Research Institute.
As previously reported by Edmunds, Sivak began publishing his study, Has Motorization in the U.S. Peaked? in June 2013 with a look at the number of cars and light trucks registered in the U.S. from 1984 through 2011, the latest year for which information was available. That data showed the absolute number of registered vehicles stood at 156.8 million in 1984, peaked at 236.4 million in 2008, and then dropped off to 233.8 million in 2011.
Since then, Sivak has released an additional five volumes of the study, all of which support the idea that our love for our cars appears to be on the decline.
The second part of the research concentrated on the number of miles driven — per person, per licensed driver, per household and per registered vehicle. In each case, the number of miles increased to a peak in 2004 and then declined.
In Part 3, Sivak came at the issue from another angle, studying the amount of fuel consumed by light vehicles over the years. Again he analyzed the gallons of fuel used per person, per licensed driver, per household and per vehicle. And once again, the numbers peaked in 2003 or 2004 and then dropped off.
Of course, during that time period technology was being introduced that steadily increased vehicle efficiency. So it's not surprising that, as Sivak writes, "the decreases in the fuel-consumption rates between the peaks and the 2011 values (13 percent to 17 percent) are greater than the corresponding decreases in the distance-driven rates (5 percent to 9 percent), reflecting the added contribution of the improved vehicle fuel economy."
The fourth part of the study took a particularly interesting view of the data: How many of us are going without cars altogether?
Using a two-pronged approach, Sivak found that the proportion of U.S. households without a vehicle decreased from 2005 to 2007, increased from 2007 to 2011, and decreased again — very slightly — from 2011 to 2012. But among the 30 largest U.S. cities, the study showed that there was an increase in the proportion of households without a vehicle in 21 of them, and in six of those cities at least 30 percent of households have no vehicle.
Part 5 of the study updates much of the previous data through 2012 and shows most of the trends continuing.
The latest volume, Part 6, which was just released in mid-December, examines the relationship between road use and economic activity, from the end of World War II to 2012. Specifically, Sivak looks at the number of miles driven and gallons of fuel consumed in relation to inflation-adjusted GDP (Gross Domestic Product).
When it comes to distance driven per thousand dollars of GDP, the miles reached a peak of 247.1 in 1977, up 42 percent from the 1946 figure. The 2012 value was calculated to be 193.2 miles per thousand dollars, 22 percent lower than the maximum and comparable to figures from the late 1940s.
The amount of fuel consumed in comparison to the GDP tells a similar story. The peak of 20.5 gallons of fuel per thousand dollars was reached in 1972. The 2012 value — 11.0 gallons per thousand dollars — is 46 percent lower than the peak value and even below the late 1940s numbers.
So what does it all mean?
Although the study is highly data-driven and analytical, rather than speculative, Sivak does make the point that the onset of the downward trends — of the number of vehicles on the road, miles driven, fuel consumed and vehicles owned — precedes the beginning of the recession in 2008.
As a result, he writes, "the reductions in these rates likely reflect fundamental, noneconomic changes in society (such as increased telecommuting, increased use of public transportation, increased urbanization of the population, and changes in the age composition of drivers), with economic factors being contributing factors only. Therefore, these maxima have a reasonable chance of being long-term peaks as well."
Edmunds says: If the trends identified in this study continue, is it possible that we'll see less traffic and shorter commute times?