If you look carefully at the various island maps the locals will hand to you, you will notice the red writing all over said maps: 'do not go here or there, this would be a violation of your car rental agreement'.
Being who we are, we happily ignored these warnings and made sure to visit these very areas.
Basically, they do not want you to drive there because these areas have not yet been 'tourist upgraded'.
Of course, it is their very wilderness that makes them so appealing to us.
The black specs: cows. Mary was thrilled. The bovine population is everywhere on this island.