Underneath the slab, 14 covered lanes, including two main thoroughfares (the Builders' Lane and the Sculptors' Lane), are undergoing a facelift to bring them up to standard.

Objectives:

• Securing the routes of the Builders, Sculptors-Pyramids (BSP)
• Integration of soft modes: pedestrians and bicycles (BSP)
• Requalification of roads by creating clear and bright environments
• Improvement and optimization of logistics flows
• Cross-connections between Sculptors-Builders roads amplified to ensure cohesion and permeability of the whole
• Modification of the road network
• Entrances to covered roads necessarily of high quality

The Sculpteurs route is a 650-meter tunnel, while the Bâtisseurs route is 725 meters long. These two main routes serve 25 towers. Now used mainly by vehicles, the Paris La Défense public authority is encouraging the towers to review their layout and entry points so that cyclists can find their way around, with services such as secure parking, lockers, and even showers available at the foot of the towers.

This project will enable the underground routes to be refurbished, making them more pleasant and bringing them closer to the status previously attributed to the surface. In other words, the underground routes would no longer be transit areas, but pleasant, safe, and clear spaces that cyclists and pedestrians could use. This will also help to avoid the numerous conflicts of use that have become all too common on the slab.

An investment of €100 million is planned for the redevelopment of these passages. The project is ambitious and could lead to the creation of delivery and waste collection areas, dedicated two-way cycle paths, small squares, and ceiling formwork to improve aesthetics. It also includes the installation of air vents for air circulation and natural light penetration, and the creation of a lighted path with color codes to help people find their way under the slab... the project is ambitious.

From a more general perspective, this project aims to improve user safety and preserve activities in the event of a fire on the tracks. In addition, these regulatory measures will enable urban intervention by introducing pedestrianization and soft mobility (bicycles) on covered tracks.

To support the use of the tracks by soft modes of transport, the project includes four openings (also known as hoppers) in the slab, which will contribute to the implementation of natural ventilation, thereby improving the safety of the structure in the event of a fire. These four new openings, distributed along the Sculpteurs track, complement the existing openings.

The four hoppers will be located at the Agam basin, at the foot of the Ariane and Total Energies towers, and at the Adagio La Défense Esplanade aparthotel.

Before 2019, around 600 cyclists crossed the Pont de Neuilly every day. In 2020, there are 6,000. While initially a route was proposed with “coronapistes” and a guide on the slab (a green strip drawn on the ground to bring them together), it is now time for the public institution to return this mode of traffic under the slab, offering cyclists safe and efficient dedicated facilities. This period has shown that these facilities work and that they should be made permanent.

Duration of works: 31 months :

• Completion of work on the Builders' Way in 2025
• Completion of work on the Sculptors' Way and Pyramids in 2026

Before 2019, around 600 cyclists crossed the Pont de Neuilly bridge every day. In 2020, there are 6,000!