Another reason due to that at night when the headlights of the
cars was switched on, the back light is on too (dim light). Though
when stepped on the brakes, the brake light will be brighter but
some people will just tend to misque it, and its very dangerous.
Some old cars dim and bring brake light got not much difference,
which is worst still. That’s why they need a 3rd brake light. You
won’t miss it one.