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 two limestone plateaus, the Causse du Larzac and the , and is inside the perimeter of the Grands Causses regional natural park. The Millau Viaduct forms the last link of the preexisting A75 autoroute (known as "la Méridienne"), from Clermont-Ferrand to Pézenas (to be extended to Béziers by 2010). The A75, with the A10 and A71, provides a continuous high-speed route south from Paris through Clermont-Ferrand to the Languedoc region, and through to Spain, considerably reducing the cost and time of vehicle traffic travelling along this route. Many tourists heading to southern France and Spain follow this route because it