Is the use of "Nite Shades" on taillights legal?

Brent P wrote:

> In article >, Steve wrote:
>
>>Brent P wrote:
>>
>>
>>>In article ich.edu>, Daniel J. Stern wrote:
>>>
>>>
>>>>On Fri, 6 Jan 2006, Steve wrote:
>>>>
>>>>
>>>>
>>>>>>On some makes and models, the front signalling lamps don't deteriorate
>>>>>>as fast or severely as the adjacent headlamps.
>>>>
>>>>>Perhaps UV emission FROM the headlamp itself contributes to faster
>>>>>deterioration?
>>>>
>>>>Yep.
>>>
>>>
>>>In addition to the sun, but I would guess not enough to actually damage
>>>the lamp by itself since the inside surface is usually not deteriorated,
>>>just the outside.
>>
>>The amount of UV that comes off the filament of a halogen capsule is
>>rather amazing. And I'm not convinced that all the apparent damage IS on
>>the outside.
>
>
> The once completely fogged over headlamp from my car is now sitting on a
> desk in my bedroom in very acceptable condition. I polished the outside,
> the inside is not accessible.
>

I wonder if the UV protective layer deteriorated first, since it is
designed to absorb UV. If its only applied to the outside, that would
explain a lot. It would receive damage both from the sun AND from the
headlamp filament.