I agree so much with NS, and just wish to add this much more,
I am willing to wear a bright yellow-lime 3M striped safety Tee shirt
gotten at THD (vests also are good), and wear it for most every ride,
and I will not wear a helmet (ruins the fun, the freedom, the air),
and I have a bright tail light for night and dusk, and an always-on,
flickering headlight too, and that lime-yellow shirt is nearly luminous at night.
Bottom line, cars, in passing me, give me tons of side room, almost always.
I look so visible, and so vulnerable, no helmet.
In contrast, many or most road bikers are in lycra which, to a color blind guy like me,
colors that may nearly blend to the general background (yellow-lime, does not),
and they are head down, hairnet helmet, and "register less-so" to the brain as being sentient humans,
I feel that most drivers give road bikers less respect, than I get. I feel that if more people wore
bright neon, and yellow-green is the best and flashing lights, even in the day, anything to jar slog-mined drivers is a help,
then there would be fewer "clippings"...just my five cents. I have never been clipped yet, lucky me, in fifty years of casual riding.
ANYTHING to jar and get Blueberry drivers' attention, say I,
I already had the power source, the front hub magneto,
and had a left-over LED "see-me" light, designed to work on a wide range of voltages,
and it FLICKERS, as I am feeding it from a pulsating, or AC current source.
The FLICKERS are fast, and effective. The bike is seen, day or night, from a distance.
The tail light I am using these days is a Planet Bike, rear rack mount style, five LED,
powered by "lithium" Energizer cells, which give it a super-bright voltage source
(would not want a brighter tail lamp array)