In article , Josepi wrote:
LED tail light are not "very bright". The illumination is very poor.

However LED lights are very focused and play on the human vision system to
compete with the effectiveness of incandescents.

Many incandescent tail lights have taken a lesson in efficiency also and
many of the so-called LED taillights on vehicles are actually incandescent
bulbs. Take a closer look and you will see many peanut bulbs in a reflector
with small pockets.

My experience is that they are usually LEDs. Most but not all cars with
LED tail/brake have dimming for tail function achieved by pulsing at a low
duty cycle. (This is done because most LEDs do not have
low-current performance sufficiently predictable from one run to another
for certification.)

Such LED tail/brake lights in tail mode usually show a stroboscopic
pattern if I move my eyes while looking at them.

When will we see back-up LED lights on vehicles? Not likely in the near
future. The total luminence is not there to illuminate an area. Something
LEDs have failed at, to date.

There are now legal LED backup lights, although so far I have only
noticed these as aftermarket replacements for truck backup lights or for
manufacture of truck bodies and trailers.

- Don Klipstein )