They may be . . .
It's difficult to be accurate at the distance we view them. NinePlanets.com states approx. 1.5 kilometers thick, but Cassini will give us a lot of good data.
Also, the particles colliding would be another way of explaining the ring-spoke effect.
Voyager confirmed the existence of puzzling radial inhomogeneities in the rings called "spokes"
which were first reported by amateur astronomers.
Their nature remains a mystery, but may have something to do
with Saturn's magnetic field.
(More Saturn Stuff)
Dan