Yes, at night, flip the headlights off. Day time if necessary, high beams flipped on and off. Most appreciated by truckers passing truckers and trying to get "back in" fast to let the trucker behind him by without him losing momentum and having to down shift. Can take miles for trucks to regain speed once slowed on a grade.
Use to use a turn signal , 2 quick flashes when flashed in, now have clearance lights on there own switch
Don't do it all the time, it is not necessary, but it is fun watching for the trucker to lean ahead and look out that mirror and then dip your lights. Gives all concerned something pleasant to think about in the middle of the night.