Reducing the number of road accidents is an urgent task, the solution of which can be achieved, including by improving the design of vehicles. One of the most common causes of road accidents is the occurrence of a car skidding during braking with its subsequent exit from the traffic corridor. The effective development of new vehicle safety systems that increase its directional stability during braking and the improvement of existing systems is possible only if there are reliable methods that take into account the main parameters of the vehicle that affect its stability during braking. The currently existing methods and expressions for calculating the heading angles of a car at the end of braking have a number of assumptions that facilitate the calculations. This does not diminish their value, but slightly reduces accuracy. The purpose of this work was to clarify the methodology for calculating the permissible and actual heading angles of the vehicle at the end of braking. Within the framework of the work, theoretical studies have been carried out, based on the analysis of existing research on this topic. Based on the analysis performed, it was found that the existing methods and expressions for calculating the heading angle of a car at the end of braking do not take into account the effect of differences in the track dimensions of the front and rear axles of the car, and the center of mass of the car is conventionally assumed to be located on the longitudinal axis of the car. Evaluation of the influence of these parameters on the accuracy of calculations has not been carried out at present, there are no expressions for calculating the permissible heading angle of the vehicle at the end of braking. As a result of theoretical studies, a refined technique was obtained, including expressions for calculating the actual heading angle of the vehicle at the end of braking under various braking modes. The previously specified parameters are taken into account in the expressions obtained. An equation was derived to calculate the permissible heading angle of the car at the end of braking, taking into account the dimensions of the car, its location relative to the edge of the carriageway and the width of the lane. The refined expressions and the resulting equation that form the methodology for calculating the heading angles of the vehicle at the end of braking represent the scientific novelty of this work. To increase the efficiency of calculations according to the proposed method, a computer program has been developed. The direction of further research is to assess the adequacy and accuracy of the proposed methodology using the developed program.

The article provides substantiation for the possibility of diagnozing latent damage to car tyres by comparing the average value of the static tyre rate at different points. The degree of uneven static stiffness of the tyre along its circumference was estimated by the size of the tyre contact spot with the support surface. An original method for approximate determination of the tyre spot area contacting with the supporting surface is proposed. The results of determining the area of the tyre contact spot at various points with several values of air pressure in the tyre are presented.

The article describes a method for calculating the heating temperature of the automobile brake disc. The brake disc is considered as a finite set of "cells" located in several layers. In thermal calculation, according to the proposed method, the heating of the disk surface is taken into account not only from the absorption of the vehicle kinetic energy, but also from the generated electric currents that cause micro-explosions between the irregularities of the disk surface and the brake pads. The cooling of the disk during the time between braking due to heat exchange with air is also taken into account. This method provides the ability to calculate the temperature of the brake disc, both on its surface and inside.