Pennsylvania recently joined the list of states that have codified common sense, so you must now turn on your headlights whenever you are using your windshield wipers. I have searched but have not found anyone addressing the question of windshield treatments that make wipers unnecessary.
So, any thoughts?
I can remember the first time I drove in a state (one of the Carolinas, IIRC) with a similar law. The signage used the phrase “must burn lights” which really left me puzzled. 
In California, it would seem that you don’t need to turn on your headlights as long as you can discern a person or another car from a distance of 1,000 feet.
–FCOD
Big fan of RainX. I use the product that goes into the windshield wiper fluid. 4oz of RainX into 1gal of wiper fluid. I’ve used the “rub on” product before, but it requires too many re-applications. I suppose you could treat with the rub-on product, then use the washer additive to maintain.
It works best in heavy conditions, and not so much for light rain. In VERY heavy rain, I’ve often found it easier to just turn the wipers off. The water beads & runs so fast that it’s like having uber-wipers :D.
The maestro of my local pub quiz* a few years ago had the OP as one of the questions one night. “By CA law, if you have your wipers on, you must also have these on.” The answer was headlights, and he informed us that he was pulled over & ticketed for exactly that earlier in the day.
*-I know, I know, but after attending for a few straight years, I’d trust him over Wikipedia any day.
BTW I also use and love RainX. It’s true, with heavy rain (going at least 55mph) it’s better to just shut the wipers off and pretend you’re traveling at warp speed.
–FCOD
I love rainx. But beware: Once you use it you will be stuck using it. As it wears off it leaves a film that is worse than an untreated window.
But a fresh coat make a rain storm much less dangerous.
hehehe. OK, we all love rain-x.
I have found a “Law Enforcement Resource” where they are discussing this topic. Looks like even they aren’t sure.
Yes, NC does require you to burn headlights when using windshield wipers. The problem is, that not only do they not enforce this strictly enough, but when I’m out in the rain **after dark ** I pass dozens of oncoming cars that are not burning their headlights. These rebels. Scary.
"Burn" headlights?! Are these signs 100+ years old?! Are they in front of signs proclaiming “Rendered Whale Blubber Ahead”?
Seriously, which of the Rain-X products do you just add to washer fluid? The washer fluid products on their site seem to just be for bugs & ice. Do you just add the regular stuff to it? Because I tried the spray years ago and it seemed to work good, but just didn’t last long enough.
No. Even if you can see them at 1,000’, you still must use the lights if the weather conditions require use of wipers.
The trouble with such laws is defining “requires the use of …” In whose judgment? 
This is the additive product Oddly, I an’t find it on the actual Rainx website. It can be tough to find, but one 10oz bottle treats 2.5gal of wiper fluid, so I don’t need to buy it very often.
Okay, what if it is a bright sunny day and you are using your windshield wiper fluid? Does the
law require that your headlights be on when the wipers are running?