The other day, a woman on a bike thanked me for stepping off the sidewalk to get out of her way. I was so overwhelmed with amazement, I was struck speechless. I couldn't even formulate a simple "you're welcome" accompanied by a hand-wave, as she rode by. That's when I realized that there's a big problem: I'm learning to take it for granted that it's my duty to leap out of the way whenever some idiot on a bicycle comes careening up the sidewalk behind me. Even the skateboarders have better manners, at least in my neighborhood.

I understand that riding a bicycle is an eco-friendly decision. I applaud the choice more and more people are making to ride bikes to work, or to shop, or just to travel from one place to another, in general.

I'd like to respectfully submit, however, that there's a reason we don't post speed limits on sidewalks. We don't post speed limits on sidewalks because we aren't supposed to need speed limits for areas designed for people who are walking. Sidewalks are for pedestrians, who don't typically travel at 30 miles per hour, or so. See, that's why they call them sidewalks, not siderides.

Bikes in traffic have my sympathy. I appreciate that negotiating traffic on a bicycle can be a hair-raising and life-threatening experience. I'm painfully aware of what that experience is like, in fact. Because every time I go out, lately, some single-minded, self-centered idiot riding a bike at breakneck speed down the sidewalk shoots me a dirty look or snarls something rude as he zings by, apparently because I didn't scramble quite fast enough to get out of his path—or maybe just because I had the nerve to be on the sidewalk in the first place, who the heck knows.  So I appreciate what it feels like to be threatened by a hostile entity with a mechanical conveyance that confers him with superior mass and speed.

So if you're that person hunched over your handlebars, flying down the hill at 25 mph, scattering pedestrians, and you just clipped that guy's hip because he failed to yield enough sidewalk to suit you? You're a jerk. The least you could do is stop and get off your damned bike and help that little old lady rescue her walker from where it got tangled with the bumper of that VW bus when she made that wild leap off the curb to keep from being mowed down by you and your Schwinn.

If you really feel you have to ride on the sidewalk, a simple, "On your left!" when you're barreling down on a pedestrian (me, for instance) would help, too, you know. Skiers and snowboarders have managed that for decades, so it shouldn't be too challenging for you to remember such a simple courtesy. Unless all that aggressive pedaling has diverted the blood from your brain to the extent that your brain's speech centers are temporarily offline.

You're actually in more danger of an accident riding your bicycle on the sidewalk, though, whether you realize it or not. And not just because if you clip my elbow with those handlebars one more time, I'm likely to jam my folded umbrella between your spokes and wrap that damned bike around your neck while you're still scraping yourself off the pavement.