ten times more likely to be hit and killed by a car while biking in South Carolina than in in Oregon. And eight times more likely in North Carolina. Other southern states have similiar, or worse, numbers.
The south is warm and mostly flat. You would think that would encourage more people to ride and drivers would be used to sharing the road with them. This Atlantic Cities article says that's not necesarily the case though and explains why the south has more bicycling collisions.