Central idea 

the poem revoles round a general problem that one ,faces in life .it is of making a choice in life. According to the poet ,by choosing a path that most people don't ba man can make a big difference in his life.in this poem ,A man came to a place where he had  to make a choice between two roads .one of the roads was obviously less travelled on  because  it was grassy and was probably more difficult to travel on , and that is the road at another times.but figure that he probably would not ,after he made his choice.the man found that he did make the best choice by choosing the road that had been less travelled by other people. The poet says that it is something  better to not make the easy choice that everyone else does, but to be willing to take a risk and be different by choosing the road less travelled by ,