When there's no junction, you don't, and in all cases green for traffic implies green for people - but not vice versa. At a crossroads traffic must be blocked i

When there's no junction, you don't, and in all cases green for traffic implies green for people - but not vice versa. At a crossroads traffic must be blocked in both directions for it to be safe to cross. A red light for traffic in one direction means vehicles travelling in the other direction could still turn left or right through it.