(Bruce Chambers/Orange County Register)

American drivers put a record number of miles on their vehicles last year -- roughly 3.15 trillion miles, or enough to make roughly 337 round trips to Pluto.

These figures were just released by the Federal Highway Administration, which says they mark an important milestone: The number of vehicle miles traveled in 2015 finally surpassed the highs last seen in 2007, before the Great Recession. The numbers encompass all types of road travel -- passenger vehicles, trucks and buses.


But the population has grown since the recession. On a per-capita basis, vehicle miles still haven't caught up to the levels seen in the mid-2000s. Vehicle miles per capita topped out in 2004, at 10,105 miles per person. Last year, the per-capita tally stood at 9,794 miles.


Still, last year was a big year for driving. Total vehicle miles increased by more than 4 percent, the biggest year-over-year jump since the late 1980s. And the reason why can be summed up in two simple words: cheap gas.

With gas currently at $1.71 per gallon, it hasn't been this affordable to drive since 2004. In places like Missouri and Oklahoma, gas costs less than $1.50 per gallon, according to the American Automobile Association.

If it's cheap to drive, people are going to drive. They're also going to be less worried about fuel efficiency. Back in October 2007, the average fuel efficiency of purchased new vehicles was about 20 miles per gallon, according to the University of Michigan. As gas prices rose, so did average fuel efficiency -- peaking at 25.8 miles per gallon in August 2014. Since then efficiency has plateaued and even declined slightly, down to 25.1 miles per gallon in January.

More driving means more congested roads, and more wear and tear on those roads too. But as usual, infrastructure spending remains the forgotten stepchild of congressional budget battles. Total public spending on transportation and water infrastructure declined from 3 percent in 1959 to 2.4 percent of GDP in 2014, according to the Congressional Budget Office.

At the federal level, the decline in infrastructure spending has been sharper, falling from close to 6 percent of all federal spending in the 1960s to less than 3 percent in 2014.

And if you drive to work -- or drive anywhere, for that matter -- this failure to fund infrastructure directly affects you on a daily basis. Consider that the typical urban commuter spends 42 hours a year stuck in traffic jams, according to a report from the Texas Transportation Institute. That number has more than doubled since 1982, when the average time stuck in traffic was 16 hours a year.


Forty-two hours is more than a full work week. Think about how much you'd pay to get a full week of your life back each year. That's a pretty good barometer of how badly we're under-funding transportation these days.

And as the population grows and drivers continue to put more miles in, it's only going to get worse.