In this work the technique of improvement of transport and technological vehicles maintenance is presented. A high-quality organization of technical service is impossible without determining the characteristics of the intensity of requests for a certain type of repair work. The failure flow as a set of successive failures of parts and assembly units is considered as a stationary Poisson process. The check of the stationarity of the failure flow was carried out using the Pearson criterion. The presented technique for researching the failure flow can be extended to any structural elements of technological machines. The results of calculations using this technique can be used, for example, to organize a rational supply of spare parts in order to reduce downtime and material losses during the technical operation of equipment.