The object of research is a polymer roadblock made from plastic processing products. The study is aimed at determining the optimal geometric and structural characteristics of the polymer block, which will provide the necessary strength when loaded by cars. Methods. Modeling of the main stresses of the block took place in the Simula Abacus software package. Results. Analysis of the distribution of compressive stresses in the initial cross-sectional area showed that peaks of compressive stresses are achieved in the internal corners of the block at the places where the load is applied. Stress concentration occurs when the cross section of the block changes abruptly. A smoother transition from one section to another made it possible to significantly reduce the resulting stress concentration. Rounding corners increases the material consumption of the block, which requires determining the optimal rounding radius.