Chris Walsh (chris_walsh) wrote,
Chris Walsh
chris_walsh

Probability

Lots of walking means lots of walking through intersections. Means you being nearer to cars, trucks, bikes, Vespas, skateboards, et cetera, all with people and all moving or about to move. So you have to watch.

Years ago I started to wonder how no matter when I was walking through an intersection, a car seemed to want to turn in front of me, going into my path. Always had to watch, because right when I happened to reach an intersection there'd be a car with a driver turning into that intersection.

With most any "always" observation, I had to realize this was a generalization. It wasn't always true, but the times when it did happen stuck in my mind more than the times it didn't. Sort of like how you think you never drive through a particular traffic light, but the times when you did sail out of your memory because they don't conform with your belief that that light always changed to red right before you got there.

I decided to think of it as a probability problem: A vehicle reaches an intersection, and has x number of ways of moving through: straight, right, left. The driver has to choose ONE of them. (If the driver chose two of them, I'd be mightily impressed. And scared. Never mind if the driver were able to go up...or down...) A four-way intersection has three possible directions to go in (33.3% chance of each); a T-intersection has two (50% chance of either); a seven-way intersection (say) has six (16.6%). Sometimes those percentages are in your favor. Sometimes they're not.

I'm telling you this because of an intersection. A Y intersection. A really awkward Y intersection.

Dig if you will the picture: SE Milwaukie Ave. northbound hangs a slight left as it passes the parking lot for Oaks Bottom Wildlife Refuge (where I went walking last night). Hanging to the right is SE Mitchell, which then bends to the east and heads downhill to SE 17th Ave. Buildings hug the top of this Y and the east side of this Y. The building within the top of the Y really hugs the sidewalk; the part of the intersection where Milwaukie is widening into two roads, the second road being Mitchell, is a wide and slanted piece of asphalt. The result is that sight lines at this intersection, from a pedestrian's point of view, SUCK. If you're northbound on Milwaukie and on the east side, either you cross that wide chunk of pavement at its widest point (not recommended, obviously, with traffic speeding by and needing to make that slight leftward turn) or you go up Mitchell almost to where it turns east and downward, then cross to the Y's top part.

My probability idea went through my head then. I thought Then don't let a car need to turn here, 'cause it'll turn right in front of me.

GUESS WHAT HAPPENED? Just when I was about to brave crossing Mitchell to get back onto Milwaukie Ave.'s sidewalk, a car needed to turn from Milwaukie Ave. southbound onto Mitchell. I waited for it to pass, and moved further up Mitchell to a narrower part of that road so I'd be safer in case any other cars needed to make that turn at that time. I moved farther into the darkness between buildings, and my defensive walking instincts were on the alert, but potential assault by a person in the dark is not as potentially physically damaging as even more potential assault by a lot of car, a potential assault that is likely to result in the need for EMTs. Yes, a car came by at that exact moment, and turned through space I'd hoped to walk through, and it's like I willed that car into existence just to keep me on my toes.

It's a strange intersection. Just accept that it is, Chris. And hope you never get killed there by a car going through. You don't need THAT lesson in physics.
Tags: peregrinations, portland
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