Sometimes I have to drive after dark in my city, and it never fails that if I drive any appreciable distance that I always see at least one person (often more) driving with their lights off. I do not need to tell y'all why this is dangerous. We're a community of enthusiasts. We know. Plenty of us are driving older cars that predate the tech.
It's not like they don't mandate lots of shit already. Seatbelts, head restraints, airbags, and backup cameras are some of the most sensible things ever required for cars to have. Why are automatic headlights not on this list? There also needs to exist a mandate whereby the lights turn on if the driver turns on the wipers. Because if you need your wipers, you need your lights too. It's common freaking sense.
Your headlights aren't just for seeing, but for being seen. Ambient light sensors are so cheap that they end up in midrange TVs all the time. I blame the backlit gauges and myriad other interior lights. Ergo, it's time to mandate automatic headlights. There's no reason not to.
I'll get off my soapbox now.
With daytime lights there's usually a module that can be added that always runs power to the lights when the engine is on. On older vehicles with regular bulbs the voltage was like 7 volts instead of the full 12 volts.
However this causes issues with the first couple of generations of LED bulbs. They usually don't come on or flicker due to low voltage.
With the newest cars this is programming option in the car menu as there are a few markets that requires daytime running lights. Sometimes it requires a dealer to make the change with the computer.