The speaker in the poem has to make a decision. Where is he located? What decision must he make?
The speaker in the poem is at a fork in the road he's been traveling, in the middle of the woods somewhere. He is now faced with the decision of which of the two roads in the fork to take, and he ponders the choice in the poem. Literally, then, he must decide which actual, physical road to take next. Figuratively, however, the two roads symbolize another choice, any choice, really, that a person might make in his or her life. This choice could be any one that one might feel would likely make a big impact on the direction one's life will take from then on: whether to go to college or get a job, which college to attend, whether to have a family, whether to take time to travel, what career to choose, and so forth. However, the speaker essentially says that all the roads have been traveled (or decisions have been made) roughly the same number of times: he says that the second road is "just as fair" as the first, that they lay "equally," and that "the passing there / Had worn them really about the same." In other words, the roads may look a bit different but are both well-traveled. Therefore, the message is not that one should make unique choices but that there really are no unique choices. It is hardly the inspirational poem that most people make it out to be.
In the end, the speaker plans to lie. When he is old and telling people about this decision he had to make, he plans to say that he took the road that fewer people had traveled, implying that he made a unique choice. The problem? There is no "road less traveled," only our very human desire to believe that we have made significant and impactful and unique choices that have made our lives our own.