Sensors embedded along highways or in traffic signals can collect data on vehicle speed, density, and occupancy, which is then transmitted through the fiber optic network for analysis and control of traffic signals or dynamic message signs. Fiber optics sensing technology can conquer this challenge with its ability to measure the vibration of passing objects along the length of a buried fiber cable. When optical pulses are injected from one end of the cable and transmitted to the other end, scattering occurs and generates. Fibre-optic sensing (FOS) is a new and cost-effective 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. This paper introduces the basic principles of several commonly used optical fiber sensors and the progress of optical fiber sensors in the monitoring of physical, mechanical, and chemical parameters and demonstrates the applications of optical fiber sensors in infrastructure. We present first result of traffic speed estimation performed.
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