I grew up in south Florida where all the streets were lined with palm trees. I never heard of a person or car being hurt/damaged by falling palm leaves. It has probably happened, but must be exceedingly rare. Then again, I never saw downed leaves along the roads or any city trucks doing pick up, so now I wonder how and when they were picked up.
Any time I visit areas with palm trees there seems to be a small army of gardeners that maintain all but the “wild” palm trees. Also pretty sure there is a cottage industry of people who harvest the coconuts.
I've seen a few fronds down in Southern California (also many palm trees there) - city maintenance picks them up I presume, and if the trees are "maintained" they don't actually drop many (because they get cut before they can fall).
