Clear writers distinguish between further and farther. The latter refers to distance and the former refers to logic. There are parts of the country (e.g., where I grew up, on the plains) where this distinction is ignored. Back home we say, “Go further down the road.” The confusion between the two is understandable. Both are comparative adverbs and separated by a single vowel. Used properly, further signals an elaboration of what was just said.
“This paving project is too expensive. Further, it is noisy.”
Going a greater distance down a road is an extension of sorts but further and farther are different words. Used correctly, one goes farther down a road and further elaborates what was just said.
This post should go no farther. I shall say nothing further on the subject.