Explain the choice of the verb "dip" in "dip your lights"

Does the phrase "dip your lights" mean to turn them off or something else? Why is the word dip used?

Quote:

If you drive with your headlights on full beam in fog, the light will just reflect back on you. Dip your lights — it will be much easier to see.

Solution 1:

To be clear, the headlights of cars today usually have two filaments.

One filament projects the beam (off the mirrors behind) straight ahead (roughly level with the road, say).

The other one projects the beam (off the mirrors) downwards (ie dipped, pointing downwards).

Thus -- when the light is on normal (that is to say, "high" beam, because the beam is pointing up high), it hits the road a long way ahead.

In contrast, when you "dip" the lights, you will see the light shining on the road a fairly short distance ahead.

They are "dipped" ... pointing-low ... the beam is pointing downwards, rather than onwards.

The thing that you dip the lights with is called a "dip switch."

(Before the 60s they were a footswitch, now they are on a stalk, or obviously just automatic.)

Note that "dimming" the lights would not help, you would still dazzle the oncoming driver. You must, of course, point the beam downwards - it's how headlights work.

I mention "bulbs have two filaments.." in the early days of motoring there were different systems to point the headlights downwards, when a car was oncoming..

'Dipping' (low beam) [ie low, downwards onto the ground] headlamps were introduced in 1915 by the Guide Lamp Company, but the 1917 Cadillac system allowed the light to be dipped with a lever inside the car rather than requiring the driver to stop and get out..." etc etc.

Dipping headlights, one of the basic elements of driving, along with brakes, turning indicators, etc!

It would appear that using the word "dip" for dipping the headlights downwards, is now more BrE. It seems that in the USA, the word has transformed to "dim." Moreover, people in the USA tend to think of the downwards-dipped beam as the "normal" one, and you then have "brights", "high" beam, etc. Physically this is completely incorrect; dimming lights would achieve nothing, you have to literally point them downwards, i.e. dip them.

Solution 2:

Generally, dipping the lights means reducing headlight intensity and turning off the ones that aren't angled toward the ground.