Hot new FRED data on vehicle miles traveled lets us construct the above chart of vehicle miles traveled per capita on a monthly basis.
You can see that driving has a huge amount of seasonality to it, but that there are also clear long-term trends. In the 1980s and 1990s, people were driving more and more. Over the past ten years, they've been driving less and less. I'd imagine that's largely explained by population aging—retired people probably don't drive as much—with the revitalization of traditional downtowns playing a complementary role.