I have replaced the tail/brake bulbs on my bikes with brigher LED bulbs, simple enough.
Since I have Givi top box mounting plates on all of my bikes, I have this setup on all of them as well. This is a Truflex 45-LED strip tucked under the rear of the Givi mount plate, attached to simple brackets I mount under the rear of the Givi plate. Since the light bar is flexible, it bends to the slight V-shape of the rear of the plate. Wired to the brake light through a simple two-dollar GS100A brake light flasher module, that flashes a few times before going solid. They make these light tubes with integrated brake/turn signal options, but I just use a solid red as a brake light only. Bright as heck.
It puts an added brake light up high, above the normal brake light, more in sight line with whatever is behind me. Plus it's clean and unnoticable when you look at the back of the bike.
https://www.customdynamics.com/red-led-t...ed-housing