When I was a little girl, we lived far enough from a highway that we didn't hear highway sounds. Those were also the days before freeways. Traffic was routed on mainly 2 lane roads across the US. Those roads went through towns, not around them.
For some reason, I wound up spending the night at someone's house sometime before I was 9 (when we moved away from there.) I don't even remember if my siblings were along or not. It was an older woman's house, and she lived on a farm along one of those highways. That night I had a hard time sleeping. I don't know why, I just remember waking up and feeling afraid. Then I heard the trucks on the highway. I knew I wasn't alone. There were other people awake and they were all right. I knew, in my child's way, that they were all right because those trucks just kept moving!
Now we live alongside a freeway. There is an almost constant sound of vehicles going by. In fact, those rare moments that there is a pause in traffic usually cause me to lift my head, wondering what is going on! But sometimes, late at night, it is still a comfort to know that there are others awake. I'm not the only one!