What figurative language is in The Road Not Taken?

In Robert Frost's much-celebrated poem, "The Road Not Taken," there is indeed a metaphor present; in fact, several. To take just one example, the road which sits at the center of the poem is itself a metaphor for a life-choice and its subsequent effects, which often are so significant that there is no going back to how things were before it (the life-choice) was made.