Profile: W.D.M. Limited is a provider of highway survey and monitoring equipment with a unique understanding of highway maintenance & asset management. Our design engineers specialize in three main areas: mechanical design, electronic & signal processing design, and high speed video & image detection. Our deflectograph measures the transient deflection of the road surface under the action of a rolling wheel at standard loading conditions to assess the structural condition of pavements. Deflectograph data is used together with a well established design procedure to estimate structural residual lives, and where necessary to design overlay thicknesses to extend the structural life.