We may have seen the highest number of cars on American roads that we'll ever see. Vehicle ownership seems to have reached a maximum in 2006, and distance driven peaked in 2004. Today, the average distance driven is back at 1997 levels, and ownership is about the same as it was in 2000. What's going on?
These figures, from the University of Michigan's sustainable worldwide transportation director Michael Sivak, are for private vehicles, not cargo-carrying trucks, but the trend shows that the public just isn't driving as much. The study, which draws on data from 1984 to 2015, counts ownership and distance driven per person, and per household, which gives a clearer view than the absolute figures, which are influenced by the U.S.'s increasing population.
As you can see from the chart, the distance driven per household rose sharply from 1984 until the early 2000s, peaked, and started to drop off. In the last year or two, there has been a small uptick, so we're not now at the lowest rate since the peak, but the trend is clear.
Vehicle ownership, too, has peaked, but the shape of the graph is less obvious. So what's causing this reduction in ownership and use? Could it be gas prices? If you take a look at the historical gas prices in the U.S., you'll see that prices rose sharply from 2002-2008, then dropped in 2009, recovering in 2012 to reach an all-time high. These numbers only correlate very roughly to Sivak's vehicle-ownership numbers, but you'd expect those to lag by a few years anyway—people don't buy and sell their cars right away based on gas prices.
But distances driven do seem to follow the rise in gas prices. As gas got more expensive throughout the early 2000s, so distances diminished. Or maybe it's just down to the fact that millennials don't care about owning cars, and can't afford to buy them or run them even if they do care.
Sivak's raw figures don't give any answers, but they can give us hope. As car use drops, so the proportion of travel done on public transit rises. And that's exactly the trend we want to encourage if we're to rid our cities of cars at last.