No, this is not a thread whose subject is about running naked in public.

At another site I read a blog with many subsequent commentors;  but this one comment I thought was particularly interesting, and the fellow, Larry, had some information I thought my fellow Beavers would find as useful as I did.  So I include it here, with a pre-addendum that, yes, Federal law requires highway vehicle manufacturers to align headlights at the factory.

"Hello.
I was, until I retired 2 years ago, a truck driver. On the subject of flashing your lights, in the daytime in clear weather, the flashing of your lights wasn’t really needed, but I didn’t mind. I’d respond with my trailer lights most times, but at night I would rather cars & RVs didn’t unless they could turn them off and then right back on. What I really hated was when cars or RVs (and trucks too) used their high beams for this purpose. Like one poster said above, it lit up the whole inside of my cab, and just when I was peering intently into my right hand mirror checking for pull in clearance, they’d hit their high beams right into my dark adapted eyes thereby blinding the heck out of me. I’d see large green spots for five miles or so afterwards. Those halogen headlights are bright enough to knock your eyes out. My advice to you if you are driving one of those vehicles that have the headlights on permanently is to just do nothing in this situation.

I have hated halogen headlights ever since they were invented because of that and people who won’t dim their lights when meeting another vehicle at night, especially on two-lane roads. They need to be dimmed at least a half mile away when meeting another vehicle at night. I realise a lot of people don’t have a concept of what constitutes a “half mile” in distance, so try it this way: when approaching headlights appear to be a single light, the vehicle is a mile or more away. When the approaching lights visibly separate into two distinct lights is approximately a half mile. A quarter mile is when you can see motion or closer. On passing at night on a 2 lane road, if the lights have separated into two distinct lights, it’s not safe. You don’t know how fast the approaching car or truck may be traveling.

Another thing on headlights: get your headlights adjusted once a year or sooner. I don’t know how many cars I have met that had one or both headlights out of adjustment, with one right in my eyes and the other so far to the right as to be useless. I met one one night that had one in my eyes, so I flashed my brights at it and the driver hit his dimmer only to have the other one in my eyes instead! It’s usually cars that have the headlights adjusted too far up or they have something heavy in the trunk or some heavy people in the back seat. LOL I see a lot of pick-ups pulling a travel trailer with too much tongue weight jacking their lights up into oncoming traffic eyes.

If you’re going to be pulling a trailer, get your lights adjusted, and on a night before you leave on your trip, go to some building where you can shine your low beams on it’s wall about a hundred feet away, mark the spot where both lights hit, then go hook up your trailer and come back and do it again. If your lights are higher on the wall than before, then you need to install load leveler shocks on the rear or adjust your tongue weight lighter or whatever you need to do to get those lights in the same place as before or just don’t drive at night.

I grew up in the fifties and I have learned to my sorrow that common courtesy, like common sense, is not so common these days…."

Larry's follow-up comment:
"Hello. This is Larry again. I justt thought of something else: As far as I know, the headlights are not adjusted at the factory. They just stick them in as the car comes down the assembly line, so you need to get them checked as soon as you aquire a vehicle be it new or used. I have noticed that most well adjusted headlights that I meet are on a police car or a big truck. I see far fewer out of adjustment on semi’s because the drivers are usually diligent about adjusting their headlights. If some of you reading this know for a fact that headlights are adjusted at the factory, post it here. I’ll bet there are a lot of people out there like me that don’t know for sure."

-Joel