Abstract
Among the motor vehicle tests there are also the tests of lateral stability. The mathematical models, which represent the subject of this paper, are models attached to this type of tests, but they can be generalized at a large range of tests included into the motor-vehicle tests. For motorcars these tests are settled by /1/, /2/, /3/, /4/. The author of the article has tried to obtain a generalization for the big size vehicles simple or articulated, as for the lateral stability tests, settled only for cars.
During the performed tests important supplements have appeared at the above mentioned international documents: the double control of the tests and the possibility of partially overtaking the tests from the physical space into the virtual one, by simulating on mathematical models on the computer. Both supplements are demands expressed by the wide -spread international documents /5/, /6/, /7/. But the international documents havent solved yet the problem of the losing stability criteria, the terms in which these criteria can be expressed in the best or the simplest way. The mathematical models lead to the formulation of such criteria. The completions and the improvements brought to the vehicle tests are based on mathematical modelling vehicle represents the topic of this paper.