At first glance this graph from Stanford University appears a little confusing, however a closer look reveals some very interesting facts on how Gasoline Prices have (and have not) influenced the miles driven in the U.S.
It Takes a Lot...
The graph above (you can see a bigger version here) shows average gasoline prices in the U.S. on the Y axis and the X axis shows average miles driven per capita each year. At first glance, you can clearly see two big spikes that represent the oil embargo and energy crisis in the 70s, and the recent increase in the second half of the 2000s.
Some of the things that jump at me:
-Gasoline was extremely cheap in the U.S. for almost 20 years. Over that period, the average number of miles driven each year per capita rose by almost 2,500.
-Even the high oil prices of the 1970s didn't do much to reduce the number of miles driven. You can see a reduction in 1974, and a small one in 1979-1980, but nothing major.
-The mid-200s were something else! Almost no increase in miles driven between 2004 and 2007 (probably because post-Katrina gas prices really scared most people and forced many to downsize to smaller vehicles and/or drive less). Then 2008 saw a reduction in miles driven, followed by a bigger one in 2009 and a further small reduction in 2010 (which was a projection at the time the data was pulled together).
So what are the takeaways here? The obvious one is it takes a lot to make Americans drive less, and it's not just that each driver drives more over time, but also that there are more drivers on the road as population increases. So what are the variables that we can do something about? A carbon tax could increase the cost of fuel, encouraging people to drive less (it could even be done in a revenue-neutral way with payroll tax cuts or whatever). Making cleaner vehicles could reduce the impact of each of those miles, potentially by a significant amount (ie. an electric car charged with renewable energy, made with recycled materials, in a factory powered by renewables, etc). And changing the environment where people live could reduce the need to drive (better designed cities, better transit, mixed neighbourhoods, New Urbanism planning, morebike infrastructure, etc).
What I'd like to see happen is a massive transition to modern transit (bus rapid transit, light rail, high speed rail, etc), more biking and walking, and private cars used only when necessary (rural areas, etc). But what is likely to happen is that we'll still see more cars on the roads, especially in the developing world, and there will be a combination of higher fuel prices, more efficient cars that eventually drop the internal combustion engine for electric motors & batteries, and more transit/biking/walking. It's better than nothing, but it's certainly not a dream scenario.