FLORIDA - The economic recession is causing bus ridership in Jacksonville to drop slightly. Whether or not fewer people are riding the bus is unclear, though - because the Jacksonville Transportation Authority says it has no idea how many people actually do.

No one does, really. Anywhere.

The public transit agency says it averaged 854,000 riders a month in fiscal 2009, down from 858,000 in 2008. But "riders" are different than people. And there is no good way to get an accurate people count.

If a person gets on a bus five times a day, he is counted as five riders.

Seniors ride the bus for free, so counting bus fares and bus passes doesn't work.

And the JTA doesn't have a handle on how many people buy a pass every month, and how many people just buy a bus pass for certain months of the year.

Mantill Williams, spokesman for the American Association of State Highway and Transportation officials, said there is no good way to estimate how many actual people ride any bus system. He said for most of them it's not important, because the focus is on demand, not individual people.

Kathy Karalekas, spokeswoman for the Hillsborough Area Transportation Authority, said ridership is counted the same in Tampa as Jacksonville. They know how many riders they have, but not people.

"If someone gets on a bus and then transfers to another bus," Karalekas said, "we count that as two riders."