Why does it mention Ya'el together with Shamgar?
Rashi: This teaches that also she judged Yisrael in her days. 1
Radak: Even though salvation came through Shamgar, it was not a total salvation; roads were empty. Even though Ya'el was esteemed, and salvation came through her, she was not the beginning of the salvation "Ad sha'Kamti Devorah" (verse 7).
One opinion in Rus Rabah 1:1 says so.
What is the meaning of "Chadlu Arachos"?
Rashi: Yisrael feared to go on the roads due to the enemy. They went covertly, on crooked paths.
Malbim: Caravans ceased. This is like "Orchas Yishmaelim" (Bereishis 37:25).
What are Nesivos?
Malbim: They are paths on which individuals go.
What are Arachos Akalkalos?
Malbim: They are crooked paths that veer from the big road to the villages on the side.
