Cornering light

Also called cornering lamp, Zone 2 lighting, peripheral lighting

A cornering light is an auxiliary light aimed out to the side rather than straight ahead, so it fills the space either side of the trail that headlights leave dark.

What is a cornering light?

It is a function, not a fixture. Any lamp aimed outward to light the verges and the inside of a turn is doing the cornering job, whether it is a pod on the A-pillar, a wide lamp on the outer corner of the bumper, or a factory lamp that comes on with the indicator.

Off-road at night, a pair of forward-facing lamps gives you a bright corridor with darkness either side of it. That is disorienting, it hides anything about to walk into the trail, and it means you cannot see the line of a corner until you are already committed to it. Cornering lights fix the sides.

Why the aim is the whole thing

Baja Designs call this Zone 2 and specify their widest lens for it, on the outside of the bumper or off the A-pillar angled outward. That last phrase is doing the work. A wide beam on the A-pillar pointed forward lights your own hood, which then reflects into your eyes, and in dust it lights the air directly in front of the windscreen as well. Turning the same lamp outward removes both problems at once, and outward is where the light was supposed to be going anyway.

They also give it a place in the hierarchy: brighter than the dust and fog lights, not brighter than the main driving lights. A cornering light that outshines your forward beam pulls your eyes off the trail.