Parking on Roosevelt Island

Here is an explanation as to why parking on Roosevelt Island is so difficult. According to this article from the Main Street Wire:

If you think it's tough to get a parking space on Main Street, you are correct. A photographic survey by a RIRA Common Council member reveals that of the 55 designated parking spaces in Northtown, stretching from PS/IS 217 to Rivercross, only 5 to 10 are available on any given day for short-term metered parking. The study found that the remaining 45-50 parking spots, or 87 percent, are occupied - the majority of them without proper permits - by vehicles that sit there for hours, days, even months.

Also,

Southtown now has 14 muni-parking spots, with two-hour limits, and will have a total of 28 when construction is completed on the remaining five buildings. That's fewer than half the spots available on one typical block in Astoria, and it's for the use of as many people as would fill up to 20 Astoria blocks.

The Manhattan Park area has metered long-term parking (up to 6 hours) at River Road and the northern end of Main Street (near Gristedes to the Fire house) as well as the Motorgate Parking facility.

According to the Main Street Wire, image is of green van that

parks for months at a stretch in front of Rivercross, unticketed.

Update - 12/10/08 - Here is some more on Roosevelt Island parking and directions.