Why two red lights (o)-(o) which flash alternately?

[Robert_Gift]

...I prefer the instant on, which is so unnatural that it attracts one's gaze...

I don't really like that because at night, they could disorient a driver, IMO.

Nice photograph, Rrxingrick!

Love the uniform deep rich red lights.

They should dim the lights at night.
But I do not understand how they would disorient anyone.
Maybe blind someone by contrast. (That is why the middle higher red brake light on a vehicle is made not as bright as the two lower tail brake lights.)

(I slept and missed my cell phone changing to 0200 at 0300.
I told all my acquaintences to be sure to remember to set their clocks forward one hour.)

[Crossingman18]

But in most cases they are MUCH too bright at night. Just my worth.

You mean like this?

How the hell does one get a shot like that?! I want to try that!

[Smjh1979]

Time lapse delay. Some cameras have this function. None of mine do.

[Robert_Gift]

But in most cases they are MUCH too bright at night. Just my worth.

You mean like this?

How the hell does one get a shot like that?! I want to try that!

12-second timelapse, if the lights blink at 1 flash per second.

[gedunk]

But in most cases they are MUCH too bright at night. Just my worth.

You mean like this?

How the hell does one get a shot like that?! I want to try that!

12-second timelapse, if the lights blink at 1 flash per second.

Which is why they appear so bright in that picture. Multiple flashes on the same section of the camera sensor (or same spot of film)
will lead to areas of over-exposure. Try doing a long exposure of a dim incandescent crossing, and it will "brighten up" quite a bit.

[CIC755]

As far as I've always heard, it was designed to simulate the old wigwag indication for "stop", but without any moving parts.

I'm curious though why a triangular three light setup wasn't used instead, something like the following to more closely resemble the old wigwag:
(o)-------(o)
----(o)----

Probably one of those cases where the answer has been lost to time.

(Edited to get diagram to look better; now it reminds me of a British grade crossing signal).

[Robert_Gift]

As far as I've always heard, it was designed to simulate the old wigwag indication for "stop", but without any moving parts.

I'm curious though why a triangular three light setup wasn't used instead, something like the following to more closely resemble the old wigwag:
(o)--|--(o)
.......(o)
Probably one of those cases where the answer has been lost to time.

My thoughts exactly!
Probably because the extra relays needed would add expense and complexity which is more prone to failure.
The two lights use just two relays, each of which builds magnetism until it draws its armature and closes its contacts, which thenergizes the other relay.
Clever thathey did not require special timing circuits to regulate the light flip-flop relays!