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A PHYSICIST WRITES . . .
(January 2004)
The word Information puts more thoughts into my head than all the other headings in the System of Car Control, combined. The main channel for the information that we take in is of course our eyesight.
A yachtsman friend once told me about a simple rule for night-time sailing at sea: if you observe a light getting closer to you, and it stays on a constant bearing (ie, its compass direction isn’t changing), then you are on course for a collision!
If we apply this situation to driving, the risks seem smaller. Let’s say there is another car on a road that is about to merge with yours, and the direction of the other vehicle (relative to your car) is constant. You might think that the danger would be obvious — by day or by night.
But what if the other car is hidden from view by your front door pillar? Worse, suppose you are also in line with their door pillar. If your two vehicles stayed on course to arrive at a point on the road ahead at the same time, then you might remain unaware of each other until it was too late to take avoiding action.
I read that door pillars are now being made thicker to improve car-body strength. Certainly mine create worryingly large blind areas. The right-hand pillar is closer to me and therefore in theory blocks out a greater angle of view. However, the left-hand pillar slopes more (from where I sit) and somehow it combines with the exterior mirror to obscure a considerable part of the world outside.
On a straight road these hidden areas sweep along with the car. But are you aware of what can happen while you are negotiating a tight bend or a corner: parts of the roadside and even slowly moving objects (often quite close to you) may stay concealed behind the door pillar on the inside of the bend, for several seconds at a time. I realized this only recently when a pedestrian suddenly appeared on the kerb as if from nowhere, as I turned a corner.
Meanwhile your other pillar — on the outside of the bend — is swinging round quickly and so may be hiding a vehicle or bicycle moving faster than you would normally expect (for it to remain in line with the pillar).
Even on a straight road, when I look around, in some ways I have a better view to the rear than to the front, thanks to the interior mirror and the two exterior ones — each of which has a blind-spot mirror stuck to it.
These little mirrors came with instructions to locate them at the inside corner of each main mirror, but I find them more effective when placed at the outside corners, giving me a view just slightly rear of sideways. Here they show either a rapidly moving reflection or an almost static one — and if it’s the latter then I know I’m about to be overtaken (or, on the left side, undertaken).
Incidentally, if you too possess these little mirrors and the shine is wearing off them, then rather than unstick the whole unit and replace it with a new one, it’s much easier just to extract the old and new reflectors and change them over.
Not that mirrors eliminate all my rear-view problems! Here are a few: reversing out of a car-park space and having to peer round the rear pillars for people and vehicles approaching from the side. Joining a motorway and trying not to be taken by surprise by a vehicle already on it. Being already on the motorway, with faster vehicles behind me on the slip-road. Remembering at night to keep my interior mirror undipped as much as possible, for an early warning of speed merchants (or flashing blue lights) catching me up.
Going back to the merging roads and the hidden car: usually the door pillar wouldn’t hide the other vehicle completely, and you may have been thinking that the visible parts of the car would be easily recognized. Alas no: the brain has its weaknesses, and you can’t always depend on it to do this identification job properly or even at all — as I will explain another time.
Peter Soul
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