Yes, the law about bicycle lights is paragraph 1 of
this statute, and states:
A bicycle, scooter or motorized bicycle or tricycle, when in use in the nighttime, must have:
A. Lighted a front light that emits a white light visible from a distance of at least 200 feet to the front;
B. A red or amber light or reflector to the rear that is visible at least 200 feet to the rear; and
C. Reflector material on the pedals, unless the bicyclist is wearing reflective material on the feet or ankles.
A bicyclist may also use optional supplementary reflectors, lights or reflective or lighted safety equipment.
I'm sure the reason for the color requirement is to be consistent with motor vehicles. White light means the vehicle is coming towards you, red means you're behind it. And that makes sense to me, so I stick to it. I imagine a motorist coming up behind you but seeing your white light (or any other color) could be momentarily confused about which direction you're going, or even what you are, until more of you comes into view. People are used to red marking the back of something up ahead.
Maybe surprisingly, the law allows either a red light or reflector in the back. So you could get away legally with just a reflector. Personally, I'm not comfortable with just a reflector, but both options have their positives and negatives. Reflectors depend on a light shining on them, degrade more in fog (the reflector's "light" is making a round trip from the car's headlights back to the motorist's eyes, compared to a bike light's one-way trip), and can get dirty or misaligned. Lights, of course, can have their batteries die. So I prefer to use both.
Actually, I just last week got a front generator hub lighting system installed, so I'll alway have lights with me. But it's about the most expensive option, though hopefully it will last a good long time. I'd been using USB-rechargable lights the last few years, which are nice and bright, but the batteries only last a few hours between charges, and I've had bad luck with the switches lasting more than 2-3 years on most of them. Cheaper alkaline battery lights have longer life, but not as bright. If you're only riding in town under streetlights, dimmer front lights might be okay. They'll still allow people to see you coming, even if they don't light your way as well.
I suppose the last sentence in statute, about optional supplementary equipment, could mean that it's not disallowed to have other colored lights anywhere, including front or back. But I think that should be in addition to the legal requirement, and I personally choose to stick to just white in front and red/orange in back, especially both a rear light and reflector(s). I feel like anything beyond that is diminishing returns.