For the first time in four years, a smaller share of Americans are driving to work alone.

The 2011 estimates by the U.S. Census Bureau [PDF] show a razor-thin decline in solo car commuting, 76.6 to 76.4 percent. Meanwhile, public transit’s share ticked up slightly, to 5 percent from 4.9. While the numbers are small — well within the margin of error — the perceived decline in SOV commuting is a departure from trends going back to 2008, when the figure stood at 75.5 percent.

The Census Bureau’s findings conform to much of the recent research on trends in American transportation, including declining vehicle miles traveled, increasing public transit use and shifting generational preferences in favor of sustainable modes.

USA Today, in its reporting on the Census numbers, credited gas prices and the bad economy. The last time there was a decline in solo car commuting mode share was when the economy crashed in 2008, and estimated car commuting dropped by more than one-half percent.

The paper conducted its own analysis and determined that transit ridership had increased in two-thirds of the 342 metropolitan areas examined. The American Public Transportation Association is reporting its sixth consecutive quarterly ridership jump, the story said.

USA Today left readers with this: “Is this a product of the current economy or is this a new normal?” That seems to be still an open question. But this is one more hopeful sign.