a path or route one passes along; a way or passage used when going somewhere.
ここが家から駅までの一番早い通り道です。
This is the fastest route from my house to the station.
祭りの日は通り道が人でいっぱいになる。
On festival days the streets along the route get packed with people.
暗い通り道を一人で歩くのは怖い。
It's scary to walk a dark path alone.