What does the road symbolize in "The Road Not Taken"? What about the woods?

The road in Frost's famous poem is symbolic of the path that one takes in life. One chooses a particular direction, and the choice determines every other event that one may encounter. One's decision of a particular route, therefore, determines one's destiny. It is difficult to determine exactly where the route will lead, and a calculated guess or assumption is all one has, unlike a physical path that one knows will lead to a specific destination. 

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The road in Frost's famous poem is symbolic of the path that one takes in life. One chooses a particular direction, and the choice determines every other event that one may encounter. One's decision of a particular route, therefore, determines one's destiny. It is difficult to determine exactly where the route will lead, and a calculated guess or assumption is all one has, unlike a physical path that one knows will lead to a specific destination. 

Furthermore, the split in the road is suggestive of the choices we are faced with on our life's journey. In the poem, the speaker chooses the route "less traveled by." The only distinctive contrast between this road and the other that "it was grassy and wanted wear" (line 8). Other than that, the two roads were mostly similar. The speaker regrets the fact that he cannot travel both roads at the same time and is compelled to decide between the two. The speaker's difficulty is emblematic of the challenges we face when having to make life decisions. Although the differences between the options we have are often very small, we have to choose and may, in future, wonder what our lives would have been like if we had decided differently—just as the speaker in the poem does.  

Once a particular choice has been made, it is difficult and even impossible to return to one's original position for "way leads on to way" which means that an initial decision determines every other event that follows. The speaker affirms the fact that one might regret or feel sad about not knowing where the other choice might have lead to:

I shall be telling this with a sigh
Somewhere ages and ages hence:

Two roads diverged in a wood, and I—

I took the one less traveled by,

The last line of the poem "And that has made all the difference" has been interpreted to mean many different things. One of these assumes that the message is inspirational and that the speaker is saying that having chosen the less common or ordinary direction has resulted in high reward. The line is understood to mean that being different and accepting the greater challenge is more beneficial. Many scholars, however, also contend that just the mere act of having made a choice is what has brought a difference and not the fact that the speaker has chosen a particular route. It takes greater courage and conviction to make a choice than to remain indecisive and noncommittal. 

The woods allude to the barriers and difficulties one may encounter in life. One's life path has to circumvent these obstacles just as the paths through the forest go around the trees and avoid all other hindrances.