Most people scan from side to side, in near, middle, and distant arcs. I prefer to scan in rays (green lines) flicking my attention between near, middle distance, and distant traffic.
The conditions in this photo – light traffic and good visibility, with no immediate threats visible – make this a good time to play, “What if?..” The red car just ahead could change lanes into the gap ahead of us, but it’s not likely, as there’s no exit visible. But is that truck safely loaded? If a ladder suddenly fell off, would the Saturn swerve and brake into our lane? Now’s the time to notice that nice wide shoulder.