Annoying anti-car headline of the day

From Richard Florida's twitter feed, I get:

One Hour Spent Driving = 20 Minutes Lost Life Expectancy:

So let us think what this means for people who drive one hour per day every day for 60 years. Expected life expectancy is reduced by 60 years times 365 days per year times one hour times 1/3 hour of life lost per hour of driving. This all comes to 7227 hours, or about 300 days. So driving every day for one hour means we lose 10 months of life expectancy (move these numbers around as you wish).

But what if we weren't able to drive at all (and buses and shared-rides vans count as forms of driving)? I am guessing we would be much poorer--mobility has at least something to do with our affluence. Maybe we wouldn't be as well nourished. Maybe we would face more economic stress. I can't be certain, but I would be willing to bet that if we stopped driving altogether, our life expectancy would fall.

I have long supported Pigou taxes on the negative externalities created by automobiles. I support subsidies for transit as a matter of social justice. But do I think cars have provided a net benefit to living standards and life expectancy? Sure!