Two roads diverged in a yellow wood
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth.
Then took the other, as just as fair,
And having perhaps the better claim
Because it was grassy and wanted wear;
Though as for that the passing there
The speaker went the other way, which looked as promising as the first. He didn’t know which would turn out better. 
 
 “Just as fair” suggests that this path is effectively  equal  to the first. Based on  the evidence the speaker has presented thus far, we can only conclude that his decision to take this road was pure caprice. 
 Misreading this line may cause a misreading of the ending: the fact that one road was slightly “less traveled by” doesn’t mean it was dramatically different, much less superior or inferior.
The Road Not Taken