A decision support unit for an outdoor lighting network (100) is disclosed. The outdoor lighting network includes a plurality of lighting units (LU1-LU8) grouped in a plurality of zones (30, 31). The decision support unit includes a controller (20) including safety monitor module (23) arranged to determine a safety factor for each of the plurality of zones (30, 31). The safety factor for each the plurality of zones 30, 31 is determined using at least one factor that represents an aspect that contributes to an assessment of each of the plurality of zones' safety. The decision support unit may also include a decision module (24) that determines a repair priority of a faulty lighting unit (LU1-LU8) using the safety factors determined by the safety monitor module (23).