Pairing: Highways and Forests
Spend any time driving through enough of the United States—like I am, trying to do a book tour—and you will eventually find yourself on a road in-between stretches of forest that go on for as far as you can tell. Highways and forest land have been a pairing since the great interstate programs linked up all the cities with asphalt black lines.
On city highways you tend to hang over the people that are moving in opposite directions than you. Sometimes, you are sunk further into the street, and it's the town that looms above you. The nature that exists on the shoulder is a grubby trash ground. Life persists, it finds a way, like the people in the city. This is not a highway, it's fast traffic.
A real highway requires nature at its sides. This pairing is inoperably conjoined. You could not sever the countryside from the edge of the road without earthworks that are beyond all engineering capabilities. You could cover the highways with a tunnel, throw dirt over it, let the green claim an equal space that we've taken away from it for cars. That would also prove impractical to build.
The forests could disappear instead of moving the road away from them. Eventually, city claims more free land all of the time. But this is unlikely to ever change the landscape to completion because there is just so much of it: even at our most expansionist human settlements tend to sprawl out, scattershot. No one wants to chop down all of those trees. Just make a straight road down the middle of them, that gets from one ocean road to a mountain where it dead ends.
This pairing isn't ideal. Nature tends not to respect the rules of the road: there is nothing to stop its denizens from crossing over from their world into our pavements. These creatures lose their lives, feed the poor, and sometimes take a few cars with them in the illuminated night. And yet, a road that moves as fast as the highway has to be surrounded by the unmovable. Otherwise, people would get hurt. Otherwise, we would be able to walk.
Image by Wikimedia user Bjoertvedt https://commons.wikimedia.org/wiki/File:Bayfield_co_HW_63_southwards_Chequamegon_Natl_Forest_IMG_1637.JPG