Luminance measurement. Luminance meters.
The Uriol and Petit Brion tunnels are located on the A51 motorway, known as the Trièves motorway.
The Uriol tunnel is located specifically in the town of Varces-Allières-et-Risset, allowing passage through the Uriol mountain on a 490-meter route and connecting the Lavanchon Valley and the Gresse Valley. It is made up of two tubes, called the east and west tubes, drilled in 1996 and 1997. The concrete-lined tunnel has an internal profile of 11.5m x 4.5m.
The Petit Brion tunnel, also made up of two tubes, is located in the town of Vif, connecting the Reymure plain, the La Rivoire viaduct and the Crozet tollbooth. It is the 94th longest road tunnel in France with a length of 595 meters and an internal profile of 8.50m x 4.50m. The explosive drilling method was used for its excavation, and it was commissioned in 1999.
For the measurement and control of the luminous intensity inside both tunnels, the DURLUM 4-20mA Luminance Meters, distributed by Durán Electrónica, have been chosen.