My life used to be dominated by quarters. Parking tickets are an important revenue source for the City of San Francisco and we have vigilent meter monitors. In most areas meters are 25 cents for 6 minutes (yes, you read that right). I'd stockpile quarters (actualy all coins) just for this purpose.
This year San Francisco has been piloting a smartcard program for parking meters. I've got a $50 card and haven't had a ticket since I got it. (Or at least not for an expired meter — they stuck me for not having my wheels curbed on a slight hill.)
The cards are stored value cards and cannot be re-loaded with more funds. (I suspect that this may change after the pilot.) Despite the reference to "debit card" on the front of the cards they are in fact smartcards, with a chip. When you first insert it into the meter the display indicates the balance remaining. Then it starts to incrementally add time to the meter. You simply remove the card when you reach the appropriate number of minutes. Voila! No more hoarding change. No more tickets!
For more info about the SF pilot (and where to buy a card) follow these links:
A recent NYTimes article describing similar technology being piloted in New Haven and other cities:
No Quarters for the Meter? No Problem
By ELLEN ROSEN
NYTimes (free registration)
Published: August 31, 2006