Auto Efficiency

One small fact in my book has caught several readers' attention:

Today, a car emits less pollution travelling at full speed than a parked car did in 1970 from leaks.

My source for this remarkable statistic was Johan Norberg's 2006 book När människan skapade världen. In a translation he sent me it reads:

the average car today gives off one-tenth as much pollution per kilometre as in 1970. The fact is that a car travelling full speed causes less pollution than a parked car did in 1970, because of leakages.

http://www.rationaloptimist.com/blog/mustang-test