I had forgotten another reason for the high rates in Louisiana. It's the only place I've driven where I recall them selling mixed drinks in the gas stations. And since you couldn't carry out an open container, they'd scotch tape on the lid to 'seal' the plastic cup, and hand you a straw you couldn't use until you walked out the door. That was several years ago, and I don't know if it is still that easy.
As for litigation, the most recent edition of the Louisiana Bar Journal urges lawyers to defend judges when the Louisiana court system is referred to as a "judicial hell hole". Also, keep in mind that tort law in Louisiana is quite different from the other states.