what are the solar panels for?

[pistonbroke]

i have often seen them on dual carridge ways scattered all over the country.(well they look like solar panels but they might not be) thanks.

[sddsddean]

Usually used for working roadside equipment in isolated spots. Things like traffic counters (induction loops in the carriageway) and meteorological/pollution equipment which is often located near roads. In the US, many emergency roadside phones are solar powered.