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
Orthotropic deck superstructure allowed bridge launching from both ends of the Millau Viaduct. The Akashi Kaikyō Bridge's orthotropic deck allowed the Japanese to build the longest span at about , or 50% longer than the Golden Gate Bridge. Orthotropic decks permit a very shallow deck depth which reduces the steepness of approach gradients and hence their costs. The form is also widely used on bascule and other moveable bridges where significant savings in the cost of the mechanical elements can be made where a lighter deck is used. The El Ferdan Railway Bridge across the Suez Canal of Egypt is the record