Is the Robert Frost poem "The Road Not Taken" about the road not taken or about the road less traveled?

I believe the poem is about both the road not taken and the road less traveled.  

That sounds like a cop out, but I believe the answer is up to individual readers. Your question is reminiscent of the age-old question of whether the glass is half empty or half full. The poem's narrator says he took the road less traveled and that doing so "made all the difference."

The narrator doesn't say whether that was a good difference, though. He doesn't say if his choice was good and beneficial to him. He simply tells his reader his choice made a difference. It's possible the poem is about the advantages of taking the road less traveled; however, it is equally possible the poem is about the disadvantage caused by missing the road not taken. By taking the road less traveled, the narrator misses the road that is more traveled. There might be better life rewards by taking the more well-traveled road, which could explain why it is more well traveled.

A positive and uplifting interpretation of the poem would say the poem is about the benefits of taking the less-traveled road. A negative interpretation might say it is about missing the road not taken.