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The authors measure and simulate the vehicle motion in situations where typical defensive maneuvers in road traffic are being carried out, namely straight braking, double lane-change (overtaking), and ramp input on the steering wheel. They reproduce the vehicle motion (i.e. velocity, vehicle's C.G. trajectory and yaw angle) by using real records or by the simulated electronic data recorder (EDR) outputs. Thus, they operate in a way that is similar to that employed by forensic experts who analyze the EDR outputs. The employed method provides means of comparing the real or simulated exact values of velocity and of the vehicle's C.G. trajectory to the readings obtained by integrating the EDR outputs simulation. Estimation of the error, produced by the expert employing the EDR outputs, can be made in this way. The results show a possibility of occurrence of significant values of the error for simplified version of the device.

The article demonstrates selected issues related to assessment of computational accuracy in accident analysis. The hereto presented theoretical grounds of the methods make it possible to consider uncertainties in the assessment of input data values. The methods were compared on the basis of their exemplary application in the case of braking process study of a vehicle in rectilinear motion. Also for the aforementioned case, the results obtained by means of various computational methods of vehicle motion (analytical and simulation models) were compared with the outcome of the experimental study.

This paper continues a subject-matter of simulation studies of a car motion with inclusion of freeplay and dry friction, but in comparison to our SAE paper 2002-01-0619 (concerning to mechanical 2WS steering systems) in this paper also power assisted 2WS as well as 4WS steering systems are also the subjects of studies. The paper presents mathematical models and simulation studies of a car handling with regard to freeplay and friction in steering system. The models are customizable for several structures of steering system. Descriptions of freeplay and friction non-linearities base on special piecewise-linear projections. Elaborated models are used for digital simulation and sensitivity analyses concerning typical open road tests of passenger car. The paper describes these investigations and presents exemplary results. They show complexity of stick-slip phenomenon and car dynamics sensitivity on the freeplay and friction in the 2WS and 4WS structures.

The authors simulate the vehicle motion in situations where typical defensive maneuvers in road traffic are being carried out, namely straight braking, singular lane-change and “J-turn”. They reproduce the vehicle motion (i.e. velocity, vehicle's C.G. trajectory and yaw angle) by using the simulated “black box” outputs. Thus, they operate in a way that is similar to that employed by forensic experts who analyze the “black box” outputs. The employed simulation method provides means of comparing the simulated exact values of velocity and of the vehicle's C.G. trajectory to the readings obtained by integrating the “black box” outputs simulation. Estimation of the error produced by the expert employing the “black box” outputs can be made in this way. The body pitch and roll are sources of longitudinal and lateral acceleration recording errors because a gravitational acceleration component for the respective direction is added in simplified version of the device.