In private communication, Roger Chittum got me thinking about the vehicle component of gasoline consumption. I’m going focus on the gross vehicle numbers, and not get too deeply into the car/truck/SUV product mix detail. Data is from the Department of Energy TRANSPORTATION ENERGY DATA BOOK: EDITION 30—2011. (Warning: 414 page pdf.)
According to Table 3-5 on page 3-9, vehicle ownership, measured as vehicles (both cars and trucks) per 1000 population, peaked in 2007 at 843.57, and dropped by 1.88% to 828.04 in 2009, two years later. Data presented in the source is from 1900 to 2009. This graph shows the data from 1950 to 2009. Recessions are highlighted in red.
During the post WW II era up to 1982, recessions might have slowed the growth of vehicle ownership, but they did not cause a decline. Even the severe recession of 1958 only caused a flat spot on the curve.
This changed with the double dip recessions of 1980 to 1982.
The reduction from 1981 to ’82 is miniscule. But since then, every recession has led to a significant reduction from the previous year. As an aside, this is one more time series that shows a change in character right around 1980.
This source indicates the most recent value for the U.S. is 765, though it’s not clear what “most recent” means. If this is accurate, then ownership has back-tracked to the 1994 level. This would correspond to a 7.6% drop from 2009, and an astounding 9.3% drop from the 2007 peak. I don’t believe it; but that value is indicated with a red dot on the next graph, as a point of reference.
I’ve also included some best fit straight lines to show how the slope has changed over time. The decreasing slope and more serious response to recessions might result from a market being close to saturation, but that’s just a guess.
One of the reasons I’m skeptical of the red dot point is that new vehicle sales have recovered substantially from the 2009 low, as this graph from Calculated Risk demonstrates. (The August, 2009 spike is the cash for clunkers event.)
This might not be enough to stop a continuing slide in the vehicles per 1000 population number, but I think it’s enough to keep it from falling off a cliff.
Another perspective on vehicle use comes from Table 3.3 on page 3-5 of the Data Book. This graph shows the Federal Highway Administration estimate of vehicles in use.
Except for recessions (highlighted in red on the total line) growth of the total vehicle count has been been quite constant over four decades. But, since the mid 80′s, car sales have been stagnant. All of the growth since then has come from truck sales. It will be interesting to see how these trends develop over the next few years.