Not life threatening
With some regularity, I see messages where someone shares their annoyance about non-illuminated rear lights in foggy conditions during the day. More than once, the term ‘life-threatening’ is used, which in my opinion is completely unwarranted.
It is usually said that a car in the distance is just visible. Indeed: visible. It’s not the first time I’ve seen a post of this kind, and at parties and birthdays, the topic sometimes comes up. Because, as the photo already proves, the car driving about 300 meters ahead is simply visible. More strongly: often you see the contours of the preceding car in the distance sooner than any illuminated rear lights. Almost all modern cars have a light switch with an ‘AUTO’ mode, combined with LED daytime running lights. Being clearly seen from the front is truly vital. For other road users wanting to cross, for oncoming traffic wanting to overtake, and on roads where trees provide a lot of shade. In Scandinavian countries, it has been common practice for years to always drive with lights on. In the Netherlands, an attempt was once made to make low beam lights mandatory during the day, but this met with resistance from environmental parties and the cyclists’ union, who felt that cyclists would then be less noticeable.
Back to cars with daytime running lights. That in itself is a good development; it prevents driving without lights in rain, fog, and at dusk or dawn. The fact that the rear lights don’t always come on is anything but life-threatening. Because, as the photo already demonstrates, you see the car well in advance, and there’s no chance of a collision. A common mistake is switching from daytime running lights to parking (city) lights. In most cases, the daytime running lights then go into a dimmed mode. It’s nice that the rear lights are on, but for your safety and that of others, it’s absolutely not advisable to drive around with a set of tea lights at the front. That’s truly dangerous. In short, if on a foggy day with sufficient daylight you SEE someone driving without activated rear lights: don’t flash your high beams, but switch to a mode of perspective and, if necessary, turn on your low beam lights.