In the poem "the road not taken" what is the symbolic value of two roads referred in the poem?

Symbolically, the two roads represent choices: literal and metaphoric. The roads are identical: this is perhaps the biggest key to the poem. Given that the roads are identical, the narrator cannot choose "the road less traveled by," because there is no "road less traveled." They look the same.

And both that morning equally lay
In leaves no step had trodden black. (3rd stanza)

This poem is often misinterpreted as being symbolic of choosing the more difficult or more mysterious path. However, given that the roads appear identical, this can't be the case. In the last stanza, the narrator foresees himself, "ages and ages hence" recounting this significant and poignant moment in his life when he is faced with a decision. As he says with a "sigh," he takes the road "less traveled by." Here, he is speculating that, in the future, he will retell this moment of decision and basically lie about it (saying he took the less traveled road), perhaps to give it more meaning or simply to be at peace with the decision (road) he chose. He "sighs" because he knows he did not take the road "less traveled by"; he just took one of two similar looking roads.

Knowing that he most likely will never return to this spot/moment, his remorse or regret is simply that he can never know where the other path may have led. In the end, the two paths do not represent a difficult road and an easy, more traveled one. They represent choice, free will, and particularly, how CHANCE can play a part in a decision; and also, how the significance of each choice can only be fully recognized or appreciated in hindsight.