Recently when we went to Brentwood for cherry picking once we were on Vasco Road (a one lane 17 mile long road connecting 580 to Brentwood) , we saw a sign which said “Turn headlights on” for next 15 miles. There were few more reminders along the way to turn headlights on.
It was a bright sunny day. I dont see any advantage to turning headlights on. (I dutifully did turn on my headlights though). It was not a curvy road either.
Similarly on Highway 152 East (when we goto L.A.) you are supposed to turn on your headlights. That is a much curvier road however.
Do you know why did the sign say “Turn Headlights on” on certains roads?
Based on my experience on driving in Utah/Arizona (where on many streches of freeways “keep headlights on” signs are visible) Generally you would see “Mirage” on the Road on the opp side of the one-lane road during a sunny day. This would hinder you seeing the vehicles coming from Opp side -in case you need to pass the vehhicle in front of you (by going into the Opp lane and pass over). By keeping the headlights on – the vehicle coming from the Opp side can see your car and you can see the other car (if they have the headlight on)
I came to the same conclusion with the addition that if a car came over to your lane to overtake some car in their lane, then there is a possibility that you may think that the car trying to overtake is actually a normal car in same direction as yours. In bright sunlight this is very possible. If they have their headlights on, you will instantly know that its a car approaching in the same lane as you.