The paper presents problems related to road safety in terms of the development of the concrete barriers system, dispersing energy of car collision on the roads with high traffic and high accident risk. Particular attention was paid to barriers’ basic parameters - weight and length of the segment. The main objective of the numeric researches was to assess the qualitative and quantitative effects of the car collision with a concrete road barrier in accordance with the standard EN 1317. To the model tests a 900 kg passenger car has been used which allowed to perform TB11 test according to EN 1317-2 standard (initial velocity – 100 km/h). Numerical studies were carried out for concrete segments lengths: 2, 4, 6, 8 m for two selected impact points. Detailed comparisons of simulation test results obtained for individual variants were made on the basis of the acceleration courses of selected car bodywork points, calculated indicators, the trajectory of vehicle movement after collision as well as on the basis of the behaviour of the concrete barriers.