At the stage of operation of roads for various reasons, it is necessary to carry out major repairs of pavement. The most common way to restore the strength of pavements in practice is to strengthen them: laying new ones or replacing existing upper layers, in most cases from asphalt concrete. The thickness of the reinforcement layers is calculated based on information about the actual and required elastic moduli of the pavement. The article discusses a number of expression parameters for determining the required strength of flexible pavements according to the normative methodology in substantiating design decisions to strengthen them. The expression for determining the required modulus of elasticity does not take into account the way the pavement is tested, and also contains other inconsistencies with the general ideas about the work and calculation of flexible pavements. It is doubted that at present the required modulus of elasticity is assigned correctly. Arguments are given about the need to link the methods of testing pavement for strength and the appointment of the required strength at different stages of the life cycle of the road