I have no idea what they are currently using, but it looks like the Stratton campaign hat below (straw, in black):
These are available at many uniform shops.
FHP calls it a "Campaign hat-Bamboo" and they pay around $65 each for them, which is about $15 less than retail for the above hat.
http://dms.myflorida.com/business_op...highway_patrol
Here is a link to Stratton:
http://www.strattonhats.com/s40.html