I just want to add my experience from the other side: Inside a car.
At night, in a sea of headlights, the light of a bicycle (especially
the bright ones) can easily get lost. Low "signal to noise" ratio if
you will. Several times over the past few years when I have been
trying to cross lanes of heavy traffic or pull out onto a road, I
have MISSED the single bright light of bicycles and motorcycles and
pulled out in front of them. Fortunately those weren't even close
calls, but I got some nasty starts anyway. "Holy crap! I didn't even
see that guy!!" Bicycles are even more vulnerable to getting lost
in the visual noise since they typically have no other running lights.
A flashing light, in addition to a bright main light, signals that
you are NOT a car. They help you be seen against all the other
headlights. Remember-- at night, that's just about all that gets
seen: the lights. You need to stand out.
This is what I keep in mind when I go out. Reflectors and bright,
expensive lights are not enough-- you have to stand out. Flash!
Ride safe.
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My father asks "Do you live here or ride a bike?"
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