Traffic congestion and higher fuel prices are driving many Long Island commuters off the road -- literally -- to use more ferries.

One of the island's more popular ferry routes goes from Greenport to Shelter Island.According to Newsday, many are turning to ferries to save time and money, which add up when gasoline is over $4 a gallon.

But the influx of passengers is a mixed blessing for ferries. Ferry operators are happy to see additional revenue and volume, but their rates are fixed by the county legislatures. Sometimes, lawmakers haven't raised fares for several years at a time.

In response, many ferry captains are trying to save fuel by aligning their vessels with winds and currents, and moving at slower speeds.