As part of the ambitious Grand Paris Express expansion, the A1 and A3 highways were closed in both directions for five consecutive nights in May, to enable the installation of a 200-meter-long viaduct. This key infrastructure element is part of the future Line 17, which will connect Saint-Denis Pleyel to Mesnil-Amelot by 2030. The viaduct was installed above 14 lanes of highway traffic a remarkable feat of engineering.

Work was carried out by NGE and Cimolai-Group for Dietmar Feichtinger Architectes, and the closures were scheduled during nighttime to minimize disruption. According to the Société du Grand Paris, a first segment of Line 17 will be operational by 2028, reaching as far as Villepinte’s Parc des Expositions station