Fiber optic sensors are becoming key tools in building more robust and accurate traffic monitoring systems. In this survey, we present various preliminary implementations and a discussion about some of the key design points. The scanning rates of the sensors should be at least 500 Hz to correctly capture the moving vehicles. The size of the sensors should not be larger than approximately 50 cm to enable individual axle detection. A minimum of 1με sensor resolution is required to detect light weight vehicles. Adaptive filtering, Wavelet denoising and neural networks are some of the tools used to improve the performance. Sensors that reside on the surface of the pavement might lead to biased data and cause destructive implementation. There is yet to be a unified solution. We need a global, user-friendly, consistent, durable, environment-friendly solution with high system availability that would work on bridges, in urban areas and in tunnels. We believe precast slabs of road pavement embedded with sensors that are manufactured at a facility would give us the best opportunity to meet those demands.