“Are Clear Tail lights legal ?”
“Yes. The Federal Motor Vehicle Safety Standards clearly state that measuring the performance and color of a lamp assembly is done with the light source energized”

It’s the color of the bulbs, not the housing. These run DUAL red running lights, DUAL red brake lights, and Amber turn signals. They comply with Federal laws, but local & state police may not be the biggest fans. These will be sold as “Show & Off-road use only” as local laws vary so much. I have had state troopers behind me with no issues.

Many cars come from the factory with Clear Lenses and colored housings.