People do not have a problem seeing me on highways. It is parking lots that are troublesome for low riders. I have to proceed with caution, because other than my flags, I am not terribly visible when they are in their SUVs and pickups. Also pulling up in the bike lane alongside cars at traffic lights can sometimes get you in their blind spot, but if you are behind them a little ways, or between vehicles to the side, you will be visible. And yes, the lights and bright colors (especially yellow pannier covers) and flags certainly help.
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What do you call a cyclist who sells potpourri on the road? A pedaling petal-peddler.