Instead of dropping 2k on a camper shell, I went all redneck and built a box to store our belongings in while moving from Alaska. It covers tha 3rd brake light. Is this an issue?

 

3rd brake light visable is NOT a DOT requirement. It does not even need to be functioning. BUT, if your other tail light is blocked you are required to have 2 functioning brake lights visable from behind. The function/installation of the 3rd brake light was from a DOT study that indicated that a raised brake light was more visable to drivers from behind and a reduced likelyhood of a rear collision.
Auto manufacturers' quickly adopted this light on most vehicles after or about 1986.

There are a few commerical toppers made for pick up trucks that don't include a 3rd brake light and they block the factory installed light that is installed on the back of the cab.

 

I'm not too concerned about it then. Thanks for the info. On I go sporting my plywood box.

 

In N.C. the 3rd brake light must be visable and functioning or you will not pass yearly safety inspection.

 

I'm confused and I think you're wrong. First, I didn't think the DOT established law. Hence, DOT does not 'outlaw' HIDs.

But, in 1986, the United States National Highway Traffic Safety Administration and Transport Canada mandated that all new passenger cars have a CHMSL installed. A CHMSL was required on all new light trucks and vans starting in 1994.