Accurate real-time traffic sensing is of key importance for optimising and managing road traffic. Often the high density of traffic sensors, needed to achieve an accurate realtime monitoring of important roads, is difficult to implement due to technical constraints or because of high installation cost. Fibre-optic sensing (FOS) is a new and costeffective alternative technology that allows a seamless, real-time monitoring of the road traffic over large distances of up to 50 km, even in remote areas such as on critical costal or mountain roads, using existing telecom fibre-optic cable infrastructure.