What to do with used motor oil?

[MsKABC]

I'm sympathetic to this view but having thought about it - what are modern roads constructed of? Asphalt and tar-macadam. And what is the binding agent they use? Tar = heavy oil.

So every time the sun shines on a road surface, or it rains, a little bit of tar evaporates or is washed to the to earth on the road side.

The tiny bit of waste oil spread on a gravel road or used to protect timber is inconsequential compared with modern roadbuilding.

Granted, but it's done under permitted, controlled circumstances, and is a necessary evil unfortunately. Waste and old asphalt is disposed of to appropriate facilities.