"The Natural Philosopher" wrote in message
...
Indicators are one at a time. Plenty of brake lights are in threes. It is
only a question of ensuriong that teh vehicle witdh is known that means we
generally have two rear riding lights.

One high intensity fog lamp that can cut through to a greater range is
better than two that can't. Peak power is what you want here.

True, but in thick fog you see a single red light that could be *any*
distance away until you get close enough (too close, sometimes) to see the
dim tail lights. That's why I maintain that fog lights should be treated as
bright tail lights, showing not only the presence of the car in front but
also give a clue about its distance away, inferred from the apparent spacing
of the lights.