Central, Peripheral and Tunnel Vision

Your eye delivers two very different kinds of vision, and confusing them causes crashes:

• Central vision — a narrow cone only a few degrees wide, where you see sharp detail and colour. Reading a number plate, judging a distant vehicle's speed: central vision.
• Peripheral vision — the vast remainder of your field, blurry and colour-poor, but exquisitely sensitive to movement. It can't read a sign, but it catches the child stepping off the kerb at the edge of your view.

The consequence: detail exists only where you are looking directly. The hazard your central vision isn't pointed at is, at best, a smear of peripheral motion — which is why "I looked but didn't see it" is a genuine physiological event, not an excuse. You looked centrally somewhere else while the hazard sat in the periphery. The fix isn't "look harder"; it's keep the eyes moving, so central vision visits every part of the scene instead of fixating.

And the field isn't fixed — it shrinks as speed rises. At walking pace you take in a wide scene; at highway speed the brain, flooded with rapidly approaching information, narrows focus to a cone straight ahead. This is tunnel vision, and it's automatic, not a lapse. Two consequences stack badly: the faster you go, the less you see to the sides — exactly when side hazards arrive faster and need earlier detection — and it compounds speed-blindness, so miscalibrated speed and narrowed vision arrive from the same cause.

The defence is the one this platform keeps reaching: speed appropriate to what you can actually take in. The road you can't perceive is road you can't respond to.