Improving position of car drivers leads to superior driving perfor-mance. Ensuring an ideal position can be achieved by real-time tracking and eval-uation of the driver's posture. Thus, this paper proposes a lower-body tracking system using inertial sensors. The developed equipment has the ability to com-pare the driver’s posture at a given moment with an ideal posture, recorded in the calibration phase, with hardware equipment. In order to compare and evaluate the driver’s postures during driving the car, a mathematical model of the human body has been developed, having as input data the measurements realized with the inertial sensors. This product contains great added value (software compo-nent) on a hardware structure (parts such as: smartphone, inertial sensors and controller) which already exists on the market.