On all the roads that I have traveled (which is only here in the North of the country and is only about 1500Km) I can say that barely a Km has gone by that I have not seen elephant dung on the road.
And pretty much all of the bush land that Ive driven through has shown lots of signs of heavy and persistent elephant grazing... All the bushes of certain types are reduced to about 2m high "posts" covered in a layer of leaves because the elephants constantly prune off the new growth.
And of course there have been plenty of "Drive-bys" of the beasts on the sides of the highway and Ive had to wait a few times while one or more cross the road in front of me... Cars and trucks can be less circumspect than I because they are significantly bigger and the elephants will move aside for them. But Im too small and they seem to like to "assert" themselves with me so I give them a wide berth :)