# Efficiency Analysis of Roadway Lighting Replacement in a Selected Polish Municipality
## 3 Results
### Analysis of the Luminaires in Terms of Illuminance
By assuming the appropriate density of road lighting elements, the analysis provides the following information:  
* Spacing of the poles;
* Height of the light point;
* Length of the extension arm;
* Inclination of the extension arm. Such information will enhance the quality of the design, but above all, it will ensure that the decision is based on a considerable amount of data. The designer and the client will know the spacing of lamps of a given intensity. The spacing of the lighting elements will be controlled in the design through intensity and cost analyses of different luminaire and support variants. A comparative analysis of the different luminaires demonstrates how the roadway illumination changes due to the same geometrical parameters of the lighting element (Figure 4). By using the same values for single-sided lighting, with the same pole spacing, the height of the light point, the length of the extension arm and the inclination of the extension arm, the BGP292 73 W 4000 K 10440 lm IK08 IP66 LumiStreet Philips LED street lamp meets the lighting requirements and illuminates the intended roadway design better than the 120 W 230 V 6000 K 13500 lm grey JASPER C82-JAS1-120 DG-6K LED street lamp. An analysis of the Philips luminaire was then performed to show how the pole spacing changes due to the height of the light point (Figure 5). The analysis indicates that the optimum pole height is 9 m. By adopting the same length and inclination of the extension arm in the different variants and with a variable value for the pole spacing and the height of the light point, the analysis shows that the sparsest possible pole spacing is 45 m. Therefore, the project used the fewest of them, which translates into the most optimal construction costs. Figures 6 and 7 show the illumination for selected Philips and Jasper lamps. The analysis shows that the illumination for both lamps is similar. The illumination in the Jasper variant is more uniform than for the Philips lamp. The illumination in the Philips variant near the light source is stronger. For the entire road surface, the illumination with the Jasper lamp is more even. Figure 3: Design variants for spun and reinforced concrete poles with single-sided and double-sided luminaires (source: original work). Figure 4: Changes in roadway illumination depending on the luminaires used (source: original work). Figure 5: Analysis of the changes in pole spacing due to the height of the light point using the Philips street lamp luminaire as an example (source: original work). A pole height of 9 m and a spacing of 50 m were adopted in the economic analyses. Thus, the same conditions that resulted from the lighting intensity analysis were met. The relevant information is that Philips street luminaires are preferred. In addition to design considerations, the model can also be employed during construction. The model indicates where exactly a given component will be installed. A work schedule created in a scheduling tool, such as Microsoft Project, can be linked to a model which includes the geometry of the elements. The schedule records which elements should be installed and when. The BIM model includes the following data about the structures:  
* Production date, in the form of yes/no information;
* Cost of the item;
* Construction cost;
* Date of planned installation;
* Date of the completed installation. Such an arrangement of parameters streamlines construction budget planning and ongoing changes. If certain items are not delivered or installed on time, construction times and schedules can be changed in the work schedule, and subsequent work stages will be updated. One plans the following stages of construction by integrating the model with the work schedule and cash flow. Once construction is complete, the BIM model will be used for the potential replacement of existing luminaires or poles. The manufacturer's data, e.g., warranty cards, can be  
Figure 6: Jasper LED 120 W 13500 lm luminance for selected lamps in cd/m\({}^{2}\) units.