Did you ever read the CAA I suggest you do?
It's illegal unless with exemption, you have an exemption from the administrator at the EPA?
Also illegal, have you read the Fast Act or asked ?
https://www.law.cornell.edu/cfr/text/49/571.108
[TABLE="class: gpotbl_table table, width: 1196"]
[TR]
[TD="class: gpotbl_cell, align: left"]High mounted stop lamp[/TD]
[TD="class: gpotbl_cell, align: left"]1 Red, or 2 red where exceptions apply. See Section 6.1.1.2[/TD]
[TD="class: gpotbl_cell, align: left"]On the rear including glazing, with the lamp center on the vertical centerline as viewed from the rear[/TD]
[TD="class: gpotbl_cell, align: left"]Not less than 34 inches except for passenger cars. See Section 6.1.4.1[/TD]
[TD="class: gpotbl_cell, align: left"]Steady burning.
Must only be activated upon application of the service brakes or may be activated by a device designed to retard the motion of the vehicle.[/TD]
[/TR]
[/TABLE]