Some notes on lighting (edited from a recommendation post made to another member), based on experiments and observations over many years of riding, mostly in traffic, some on bike paths:
Keep in mind that the smaller the lights are, the less likely they are to be seen (in daylight). Making them brighter does NOT make up for that. (I've tried out a lot of lighting setups over the years, long before I started adding motors to the bikes)
Brighter lights that are very small, especially "pinpoint", are distracting or even painful to look at in the dark, especially if the eye has adjusted to the darkness, and especially with narrow-angle LEDs with little or no diffusion.
The larger the lit surface area is, the more likely they are to be seen, even at a lower brightness level, day or night.
LED stuff generally will be lower power and probably lighter weight, but you should still use the ones with the biggest lit-up surface areas you can get or make.
Also, especially at night, the smaller the lights are the more likely others on the road are to judge that you are still far away, and that they have plenty of time (even when they don't) to do whatever they're gonna do.
The larger the lights are the closer you look, and the more likely others are to hesitate before running you over in a dumb maneuver.
People have been trained to judge distances by the size of lights on cars and traffic lights, so lights about the size of your hand (posed in a "stop" gesture, but sideways) or larger are about right for getting them to judge your distance correctly.
They may still misjudge your *speed*, but that's another subject.
And a bright pinpoint light at night may actually make someone look *away* from you (because it may hurt their night-adjusted eyes) where the same overall brightness spread out on a larger surface area is much easier to look at and won't cause them to look away.
Downlighting, like the LED strips I have on the bottom of the handlebars, cargo rack, and downtube of SB Cruiser, will light up the road around you and make you look larger (and closer), and more visible overall.
My lighting has gotten more positive comments than anything else about any of my bikes, inluding from law enforcement.
