In Lowell, MA, a parking meter was $0.25 for 15 minutes or a $1 coin for 2 hours. A 100% bonus for using the dollar coin! ^
If you think about it, it makes sense. Most of the parking meter effort has to be labor to empty the boxes and process the cash. If everyone used dollar coins instead of quarters the meters would take a lot longer to fill up, and the city saves on labor and processing costs. Encouraging use of the dollar coins in parking meters makes perfect sense.