According to system designers Alberto Battistini and Alain Mazzocchi, the original plan was to use traditional lighting fixtures for light towers and lighting poles with discharge (high-pressure sodium) light sources.
However, said the designers, the provincial government was ready to experiment in the field of public lighting and decided to set up a system that used LED technology in order to:
- save energy while providing an even level of lighting for roundabouts and access ramps;
- save on maintenance costs, thereby reducing disturbances when road work is being performed, and thereby improving user safety;
- increase highway safety and the visual comfort of users, by using a white light with a high chromatic output and exceeding the minimum values of uniformity required by the standards, for a better peripheral vision and perception of obstacles, also minimizing glare;
- comply with Law no. 17/2000 and subsequent amendments and addenda of the Lombardy Region with regard to minimizing light pollution and saving energy;
- obtain a lighting compatible with the environmental standpoint with the presence of night-time wildlife in the zone where it would be installed;
- obtain an architectonic solution of fixtures that is aesthetically pleasing.
Mazzocchi, the project manager responsible for the project, eventually chose to work with LED system modules by cor light, a subsidiary of ewo that works in the sector of development and marketing of LED technology.
Two T-System installations were used with a mounting height of 22 m and a respective connected load of 3,283 W for the illumination of the central roundabout. In total, the systems illuminate an area of over 20,000 m². The products are complemented by 24 FO systems on the approach roads.
One reason for deciding on the T-System was the modular concept developed by ewo. T-System is fitted with the required number of LED modules for each project based on the illumination requirements. In this way, it is possible to fine-tune the performance in stages to ensure that the system only uses as much energy as is required to fulfill the prerequisites. The modules can be exchanged for maintenance without the need to exchange the entire system.
The highly-efficient modules work with large-area refractive optics that achieve a precise distribution of light. The DP31 module was used for both T-System installations, having been specially developed for large-area illumination to provide a medium lighting factor of 20 lx in accordance with EN 13201 (classification CE2).
The DS31 system module was used for the FO series products, which was designed for street illumination: the approach roads are illuminated in compliance with the ME3a classification.
The LED system modules are powered with 350 mA reaching an output of 10.8 W. Nine Cree XP-G LEDs were installed per module, each with an output of 139 lm per LED at a color temperature of 6000 K.