Millau Viaduct slightest movement in the Viaduct, and measure its resistance to wear-and-tear over time. Anemometers, accelerometers, inclinometers, temperature sensors are all used for the instrumentation network. Twelve fibre optic extensometers were installed in the base of pylon P2. Being the tallest of all, it is therefore under the most intense stress. These sensors detect movements on the order of a micrometre. Other extensometers, electrical this time, are distributed on top of P2 and P7. This apparatus is capable of taking up to 100 readings per second. In high winds, they continuously monitor the reactions of the Viaduct to extreme conditions. Accelerometers
Millau Viaduct Vinci Group specialising in prestressing. It installed the cable stays and put them under tension, while the prestress division of Eiffage was responsible for prestressing the pillar heads. The steel road deck, and the hydraulic action of the road deck were designed by the Walloon engineering firm Greisch from Liège, Belgium, also an information and communication technologies (ICT) company of the Walloon Region. They carried out the general calculations and the resistance calculations for winds of up to . They also applied the launching technology. The sliding shutter technology for the bridge piers came from PERI. The bridge's construction cost