What about the emergence of two-income families? Is it possible that the per capita mileage has gone up because there are two commuters in an average family when in 1962 there wasn’t?

Looking at the years where miles-driven dropped:
1974: recession
1979: recession
1991: recession (and cheaper gas)
2001: recession (and cheaper gas)
and currently – the worst recession since the Great Depression.

It will be interesting to see if miles driven rises again once more Americans have jobs to drive to.

Now, the highway trust fund is also used to repair roads, and small portion of the money now goes into financing public transportation. So, it is my opinion that somewhat more of the money be allocated to public transit in order to curb the vicious cycle. (and bike lanes, bus lanes, and carpool lanes) I think this graph demonstrates what is so far the consensus of the other commenters: people need to drive, particularly to work, no matter what the price of gas is. Unfortunately, this systemic problem is presented to us as an individual choice/failing. This, I’m pretty sure, is counterproductive to actually substantially reducing the problem.

Commuting is just part of the picture. In my own family, I have 4 family members that commute from their farms to nearby cities to work. Once they’re there, their vehicles are parked for the day. Compare that to a family member that lives in the city, but works on sites all over the place, in and out of the city, so not only does he have his commute, but work related driving – and his work truck is practically a moving garage, saving him from having to drive elsewhere whenever tools, parts, etc. are needed. Without that, he’d be driving even more, all of it necessary for his job.

My husband and I have gone from biking as primary transportation, to needing a vehicle for commuting and because we lived in an isolated area, to relying on public transit. For health reasons, my husband can no longer commute, so we live close enough to his office that he can either walk or bus to work, even though it means living in a fairly high crime area with a high population density (given the choice, we’d be living outside the city on an acreage, but that’s not an option right now). Yet after several years, we have a vehicle again – not for my husband, but for me, the stay at home mom. There are many reasons why we decided on getting a vehicle, ranging from the cost of buying monthly bus passes for 4 people(weirdly, our city does not have youth bus passes, so we had to buy adult passes for our kids) to time. Just as one example, because of how the bus routes are designed, one particular trip I had to make regularly took 3 buses and 1 hour to get there, 1 1/2 hours to get back. Driving, it’s only 10 minutes. Plus, with our van, I can combine errands into one trip, allowing me to do 3 or 4 errands in the same length of time it used to take me to do one by bus. Compare the number of miles I drive in my van to accomplish this to the number of miles running the same errands by bus,which had to be spread out over several days due to time contraints, and it’s significantly lower.

I understand and somewhat agree with Frowner’s comment that most people are not able to simply give up their car, any more than we can simply decide to get rid of suburbs. But we make lots of small choices at various points that affect how much gas we use. For example, when buying a vehicle we can look at smaller cars with manual transmissions, rather than large SUV’s or pickups. Obvious, a landscape contractor might need a pickup, but an aide at an assisted living facility probably does not. And you can look at the bus routes for your town, and see if you could drive part of the way to work, park, and take the bus the rest of the way. When one does change residences, one can choose to move into a city rather than into a suburb.

In other words, we aren’t able to make dramatic changes in our use of oil now, because of the decisions we have made in the past. Which should tell us that as these decision-points come up in the future, we could decide to make the amount of oil we use a factor in what we decide to do.

When a person who is commuting for work faces an increase in gas prices, he or she might try to earn more money. (But going in to work on weekends, or taking a second job, means more commuting.) Or they might try to reduce other household spending, perhaps buying groceries in bulk (cheaper than the neighborhood store, but requiring more driving to buy them.)

We often talk as though it’s an easy choice to give up your car or dramatically reduce your driving–a simple moral decision, something easily done without or replaced by buses and biking. Let me tell you–I actually gave up my car, after waiting quite a while to get hired at the university in my town. I bike to work, I ride the bus a little–and I borrow my housemate’s car once a month for a giant canned goods/toilet paper/laundry detergent run to Target, because even living in a relatively densely settled area, I find it difficult to bring home large and heavy things on the bus. And for me, giving up my car was the result of luck and a lot of planning! Certainly other people could do as I did, if they didn’t have a lot of family responsibilities and they were able to live close to work in a fairly dense metro area.