The major forces acting are from frictional interactions between tire and ground. Tires are significantly compliant structures and their mountings may be flexible to some extent also. At higher speeds, aerodynamic forces may become important and they may influence vehicle motions directly or indirectly through their modification of tire loads and, thereby, shear forces.
System modeling is a central activity.
Standard, simple models are commonplace in teaching. They may also be used to resolve generic issues or may be built into chassis control electronic systems. Complex models are necessary for predictive design. Electronic chassis intervention systems and problems arising in connection with combination and single track vehicles are also important issues.