Thus to create a good lighting environment for the traffic squares, we should not only pay attention to the horizontal illuminance, but also vertical illuminance within the space.

Paradoxically when there are most sunspots, overall solar output - called total solar irradiance (TSI) - is also at a high.

We don't see lux levels, we see the light reflected from its surrounding spaces, hence understanding of materials, colours and how it interacts with lighting is crucial for a good lighting design!