In the paper, the model of estimating the loss of maintenance potential of high mobility wheeled vehicles within proving ground tests is presented. This problem is up-to-date, especially important for military vehicles. The authors have analysed the selected requirements directed to this class of vehicles. In the main body of the paper, some model that could be applied in on-line system of prognostic Health and Usage Monitoring System (pHUMS) was presented. This model can be used to analyse information about the maintenance process of vehicle before some maintenance decision would be made.