The Persistence Of Vision
I also have slow reflexes and poor balance, stemming I suspect, from being dragged head first with a forceps out of my mother's birth canal while she was too doped up with ether to contract. Ether was a tremendously nasty anesthetic. Modern alternatives like Darvon are a great leap forward.
So I learned, after an avoidable [at least for someone with normal reflexes] rear end collision at 25 mph in my youth, to allow extra stopping distance, and to take advantage of my exceptional eyes to regularly track traffic behavior to the far distance of my clear vision. This is about 5 short city blocks. Most people I know can see with this clarity only for about 3.
When I wait for my bus in the morning darkness, I get an oblect lesson in the mechanism of perception. Five blocks from me is the right turn that the bus makes onto the street of my stop. I can only see the bus lights as it turns. If the transluminated sign with the route name and number is clear and bright, it is easy for me to tell it is my bus. If not, then not.
COTA has several different ages of coaches, some brighter, some dimmer, so I often can see only the headlights and the yellow lights that decorate the top, the sides, and the front of the coach facade. School busses, and many medium size trucks have a similar yellow light pattern to my bus: three lights bunched together top center, and two lights each spaced down the sides.
Perception is a sorting mechanism that operates by discarding alternatives. When the large vehicle, with the typical light pattern, turns the corner, my perception immediately discards all possibilities [motorcycle, car, SUV, minivan, step van, pickup truck] except for transit bus, school bus, and truck.
The next level of differentiation is about four blocks away. At this point, driving behavior comes into play. A turn or a lane change to the left center lane eliminates a transit bus, leaving school bus or truck. And a fast, leadfooted, barreling down the street is immediately distinguishable from the stately progress of a transit bus scanning the curb for customers at the stops.
But sometimes such distinctions are not there, and two blocks remain before new evidence emerges. At this point engine sounds become distincter, beyond just "diesel", which I can hear a little further away. The Blue Bird school bus typically revs far higher and sounds more treble than the deep base of a truck, whose powerful lower gears are there to manage downshifting to slow while completely loaded. The transit bus has its engine under the driver rather than in front of him, and has a gravelly baritone from being muffled by more surrounding mass.
In addition, at two blocks, the angle that the vehicle presents to you finally becomes obtuse enough to see the outline of the vehicle's mass. So, at this point, a school bus finally distinguishes itself from a truck as well as from a transit bus, and I start searching for my bus pass--if it is my bus which is coming.
Thus perception. Knowing when and how to discard alternatives is the key to its accuracy. This is the case with the perception of people as well as things. Perhaps some of the more fantastic narratives I read on blogs about Muslims, about Liberals, and about the attitude of the secular world toward Evangelical Christianity come from simply wishing to hold too many cards.