PORTLAND, Ore. (AP) — Many cars and trucks have vanished from downtown Portland since the start of July.

Where they have gone is a mystery, but why they are gone is not.

Since July 1, motorists with disabled placards have had to pay for metered parking spots. Before the change, it was common to find blocks in which every parking spot was taken, and almost all the cars displayed a placard.

Now there are many empty spaces.

Parking code enforcement officer Becky Rhodes says she saw a dramatic change on July 1 and thought it might be partly due to the Fourth of July holiday. But it has continued.

The city ended free, unlimited parking for people with disabled placards to boost turnover and meter revenue.

Parking remains free for those who use wheelchairs.