Road fatalities starting to creep back up
Road fatalities plunged an unprecedented 26% between 2005 and 2011.
Now, to be sure, driving was still the most dangerous thing that most of us did during that time.
In 2011, 32,310 people lost their lives in a traffic accident.
But put in context, that number is astonishingly low.
The last time fewer people died on U.S. roadways was in 1949 - and that was with 83% fewer vehicles on the road.
But there are signs of trouble ahead.
The University of Michigan Transportation Research Institute notes that the most recent data shows roadway fatalities creeping up.
UMTRI says there's no doubt that vehicles became safer between 2005 and 2011. Many more cars have airbags - often multiple airbags - along with electronic stability control, which keeps people from losing control of their vehicles.
And the basic skeleton of most cars is better designed to withstand a crash and keep the humans inside alive.
More states also adopted graduated driver-licensing laws to make sure teen drivers get more time behind the wheel with an experienced adult riding along.
But UMTRI's Michael Sivak warns that we're likely to find that the largest single factor involved in reducing traffic deaths was the state of the economy between 2005 and 2011.
His analysis notes that people drive less during economic downturns - and they drive fewer miles on rural highways, which are more dangerous than urban settings.
People also slow down to conserve fuel. And recessions mean fewer large, potentially dangerous trucks on the roads.
Now that the economy is improving, traffic deaths are creeping up.
Sivak says the preliminary data is "the canary in the coal mine." There was an 8% increase in the number of fatalities in the past seven months, compared to the same period last year.
In the long run, people hoping for a similarly large drop in roadway fatalities may have to look to emerging technologies, in particular, car-to-car communication systems that involve driver warnings and automatic braking to avert accidents.
UMTRI and NHTSA are currently conducting the largest trial of such technology, involving hundreds of vehicles equipped with transmitters and receivers.