Optical fibres have been used for developing variety of sensing configurations for monitoring a wide range of parameters. This thesis presents the design, construction
and characterisation of a new type of single-transducer optical fibre Weigh-ln-Motion (WIM) sensor. The sensor is based on an extended (long) fibre optic Fabry-Perot interferometer. The Fabry-Perot arrangement was chosen for its simplicity, sensitivity, low cost and ease of installation.