In , Gordon
Burditt wrote:

A lot of new cars already come equipped with LED tail Lights. They are
very bright, and if one LED fails, you still have a lot of light. The

According to state and/or Federal regulations, if you're driving
with a tail light with one burned out LED, do you deserve a ticket,
even if you still have a lot of light?

If the light continues to meet the specification of upper and lower
limits of candela in all required directions, then there is no way to
deserve a ticket. If the percentage of LEDs being failed is small,
chances are fairly good that the light will meet every letter of the legal
requirement.

Sometimes what appears to be redundancy actually increases the
failure rate.

I would agree that a multiple LED light is likely to fall short of the
spec sooner than a single-LED one is. However, since red LEDs usually
honestly achie 100,000 hour life expectancy (white ones generally don't),
I expect a multi-LED tail/brake light to meet the spec until the light has
been used a few tens of thousands of hours. More, since most of the time
it will not being used at full power as a brake light.

In a Crown Vic used as a police cruiser and after that as a taxicab,
lights may have to run for a few tens of thousands of hours. Otherwise,
any decent brake/tail or turn signal LED light should have little trouble
outlasting the car unless it gets broken in a collision that does not
total the car.

- Don Klipstein )