Was driving my 2023 GMC Sierra in a mild snowstorm after leaving the grocery store and heading home. It was about 10 minutes after dark and it has just started snowing. I was only 5 minutes down the road and the visibility in front of me suddenly & drastically declined. I could barely see the road. I could barely make out anywhere to turn out to. Once pulled over, I walked to the front of the truck and the headlights AND fog lights were completely covered in snow. I wiped them off with my hand and could then see great again. Well, 5ish minutes down the road again and they were back to completely covered. Twice I wasn’t able to pull over, due to the steep terrain and no shoulder so, I had to push on, traveling at no more than 4MPH. And getting out during one of the 7 cleanings, I almost slipped and fell. It took me 48 minutes to get home. A trip that usually takes 25! The HID headlights on my other truck don’t have this problem. And the aftermarket LED headlights on another vehicle of mine have built in heating elements. You would think the M would’ve thought of this option but, they don’t offer it! If it wasn’t for my 20+ years experience of driving in the snow, I would’ve been left stranded or wrecked/totalled the truck due to this major safety oversight!