Originally Posted by
Roody
It was an unclear sentence, further confused by mention of an Australian researcher or some such.
Regardless, a per capita drop is still a "real" drop. It's just one way of measuring it that in some ways is more meaningful, since it points out trends and personal habits. In addition, real miles driven have dropped in the US, as I said. The article says that US miles are at the same level as in 1998. Since population has increased quite a bit in 13 years, this also implies a per capita drop in the US.
Okay.
If the population of a town is 10 and they drive a total of 1,000 miles, then the per capita milage is 100. Two years later the per capita milage has fallen 10% to 90 but on counting the inhabitants we find the population has risen 10% to 11. Under this scenario the total milage must have been 990 which represents a drop of only 1%. If the population had doubled, a 10% drop in per capita milage would mean they had driven a total milage of 1,800 or an 80% increase.