Those are great questions! And I appreciate the sincere follow up!
Deer are social creatures. They use their noses and tongues to often communicate either by direct contact or by licking the same branches/or things of the like. CWD, chronic wasting disease, which will kill the deer, is spread from deer to deer by mucous/saliva. So when deer are not left to be able to roam it’s more likely they will infect the entire population.
When hunters are in known CWD counties, they will send samples of their deer to scientists. These are funded by proceeds from the hunters costs to buy permits/tags/etc. The data collected allows the state game agencies to make decisions that are best for the population of deer as a whole.
I don’t have the data to support the car facts but you can research your local state game agency for their statistics and cross referencing with deer related accidents in the area. All that data is funded again by proceeds from hunters.