Modeling of pavement response is central in mechanistic pavement analysis and design. Hence, the validity of response models is an important prerequisite for reliable evaluation of structural pavement condition. As measurements of pavement response at several pavement tests have shown a lack of fit between observed and calculated response using state-of-the-practice response models there is a need to focus on the validity of these models. An instrumented field test pavement was established on top of a sandy material sufficiently thick to be considered a halfspace to allow verification of pavement response for both the simple case, a halfspace, and for the more complex case, a multilayered flexible pavement. Falling Weight Deflectometer (FWD) loads were applied at each layer of the pavement to provide input to built-in instruments, which registered stress and strain in three orthogonal directions in the sandy subgrade. At each pavement layer additional FWD and surface wave measurements were carried out at several locations to determine elastic layer moduli. The experimental results showed good agreement between elastic layer moduli from the FWD backcalculation and moduli from the in situ response observations. Results from the surface wave tests did not compare well with results from the other tests