In this paper, experiments of one-dimensional plane plate impact on polymethylmethacrylate (PMMA) targets are conducted, in which dynamic transverse stresses induced in the targets are measured using a new type of manganin piezoresistive stress gauge having 50 Ω low-pressure narrow grid-like foil. It is shown that this new instrument can improve measurement accuracy remarkably by reducing the so-called strain effect. Moreover, relationship between shear stress and longitudinal stress within a certain range of the latter is obtained.