I wonder if visibility could be helped by leaving some flashing in the tailights when they're full-bright : when the brake-light mode is activated.

(I mean LEDs that are dimmed by flashing them on and off at a rate faster than persistence of vision.)

Another visual thing. This is a pet peeve. Emergency vehicles use flashing BLUE lights. That's perceptually stupid. For one thing, human eyes, opened up (wide pupils, typical at night) do a better job of focusing longer wavelength light. This has two consequences: -- it's slightly harder to locate the source of the light because it isn't as neatly focused on the retina. -- the poorly focused blue light splatters all over the retina, desensitizing the rods of peripheral vision and spoiling dark adaption right when it's needed - entering into a zone where an emergency vehicle is active.

Secondly, red light-- deep red light -- selectively desensitizes the cones in the fovea, leaving the rods in peripheral vision sensitized.

Conclusion: orange light would be a much better choice than blue for cop car flashing lights. It would focus better, preserve dark adaptation better, and preserve nighttime peripheral vision better.