This part of the European Standard defines how to calculate the energy performance indicators for road lighting installations using the calculated power density indicator (PDI) D P and the calculated annual energy consumption indicator (AECI) D E. Power density indicator ( D P) demonstrates the energy needed for a road lighting installation, while it is fulfilling the relevant lighting requirements specified in EN13201‑2 . The annual energy consumption indicator ( D E) determines the power consumption during the year, even if the relevant lighting requirements change during the night or seasons. These indicators may be used to compare the energy performance of different road lighting solutions and technologies for the same road lighting project. The energy performance of road lighting systems with different road geometries or different lighting requirements cannot be compared to each other directly, as the energy performance is influenced by, amongst others, the geometry of the area to be lit, as well as the lighting requirements. The power density indicator ( D P) and annual energy consumption indicator ( D E) apply for all traffic areas covered by the series of lighting classes M, C and P as defined in EN13201‑2 .