In most of the US, bicycles are seen as kids' toys, sports equipment or the absolutely last resort of the desperately poor.
They kind of fly under the radar as far as most laws and city ordinances are concerned.
In my area, bicycles are, for example, technically considered 'vehicles' with the same rights and obligations as a motorcycle, car, etc., and are as such not allowed to be ridden on sidewalks, but people do it all the time anyway and I've never seen anyone get in trouble for it.
I guess the cops would rather let the cyclist break the law than having to scrape his or her broken, mangled corpse off the road with a putty knife.
Which is what might happen if the cyclist would actually insist on some of those rights they technically have......
Anyway, in regards to your question, in my area, the only legally required safety features on a bicycle are at least 1 reflector per wheel, so every bike sold must be sold that way.
Most people remove them as soon as they get the bike home, because they are not 'cool'.
Very, very, very few people would even think of riding a bicycle at night or in weather conditions that would require lights, and the ones who do usually have neither reflectors nor lights and prefer dark clothing.
Why are the streets not littered with dead cyclists?
Because there aren't very many.
Personally, I like to use one blinking light in front (current color greenish) and a red one in the rear plus wear a reflective little vest thing. Blinking lights attract the eye more than steady lights and if you live in an area where drunk and/or drugged driving is the norm, you want to attract the boozy, coked-up eye as much as you can.
I also have reflectors, 2 per wheel.
The lights are attached to the stem and rear rack via screws, clip-ons are way too easy to steal.