A recent Miami Herald article says the No. 1 reason given for owners taking pets to shelters is moving. Often, foreclosed owners can't find rentals that will take pets. And Realtors are finding pets left in foreclosed houses without food or water.
I read that many homeless people move into their car with their pets, and I know that happened with at least one person here in Modesto.
The New York Times said many such people want to keep a low profile, but they have to be near shower and restroom facilities, as many have jobs.
In contrast, a recent Seattle Times article said their area was having problems with "rolling slums" -- car colonies with as many as 100 people. Businesses complained these colonies obstructed customers, who couldn't park near the business. Plus, they built campfires on the sidewalks.
Right now, the only solution is to shoo the homeless away. Santa Barbara passed a law limiting the size of car colonies to five. The city allows them to park overnight in church and business parking lots, but the cars must be gone in the morning.
With the price of gas, I don't think they can travel too far.