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Comment by phkahler | Hacker News Reader

One that I hate is GM cars that turn on the "reverse" lights in parking lots when the car isn't even turned on, or sometimes when there isn't even a person in the car. I'm sure someone wanted to turn those on as a convenience for people or maybe to indicate there is a person nearby? But those lights have a specific meaning which is no longer reliably conveyed by GM cars.

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I was curious, so I just checked the FMVSS requirements for these[0]:

Must be activated when the ignition switch is energized and reverse gear is engaged. Must not be energized when the vehicle is in forward motion.

Seems that should be amended to not allow use when the vehicle is in park, just as they are prohibited while in drive. I'm tempted to write to the NHTSA and propose this change.

[0]: https://www.ecfr.gov/current/title-49/subtitle-B/chapter-V/p...

I think this might be a disconnect between what those lights are "really" for, and how they're actually used (de jure vs de facto, in a sense).

They aren't meant to have a specific meaning, they're just headlights, but when going in reverse. So if the car has a feature to "turn on the headights" it makes sense to activate the ones on the back too.

Though that's just pedantry that kicks the can down the road to the question, why are the headlights turning on with nobody in the car?

They are definitely intended to have a specific meaning (like turning indicators, but for backwards).

The specific use is to light the way when reversing. They are not intended for use as "reverse" indicators, even if that's what they're used for in practice. Trailers usually don't have reverse lights, for example.

Yeah, you could have a whole article-length rant about how courtesy lighting has devolved into turning parked cars into simulations of a rocket launch site lit with flood lights.

The dwell time on these modes is so long that you need a welding mask to protect your eyes if you make the mistake of waiting in a supermarket parking lot for someone who is running a quick errand. Just a constant stream of large, unattended SUVs blasting ridiculous light into surrounding cars. By the time one turns itself off, the next one is ready for duty.

Not really, there seems to be a specific rule that you can’t turn on the back-facing headlights when you’re going forward.

https://news.ycombinator.com/item?id=44789587

I don't think that rule matters here, because the car in question (in phkahler's comment) is stationary.

They do this to help people see around the car at night. The reverse lights only turn on when the car is off. They also time out and turn off automatically after a short time.

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