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A method for evaluating a driver's response in a nighttime crash scenario is offered. A pedestrian can be said to be within the headlight beam when the line representing the shape of a headlight beam equals the pedestrian approach vector. This method is based upon headlight beam mapping and the illumination necessary for drivers to recognize non-illuminated objects on an unlit road at night. The most notable information gained through this research is to be able to correlate headlight illumination with driver response distances. From 25 nighttime driver response distance experiments, information was gathered from many of the original authors. This information includes position left or right, headlight type, lighting, movement of the object or pedestrian, and the position (standing, slumped or laying).

The problem of uncertainty is particularly important in the analysis of accidents involving pedestrians because even slight but simultaneous modifications of many data can result in shifting the responsibility line. Calculations include a number of irreproducible parameters whose numerical values are either selected from literature (e.g. reaction time, lag time, friction coefficient) or on the basis of verbal description (e.g.: “…when he was still running along the sidewalk, it was obvious he was going to rush into the roadway”, “the car wasn't braking too hard”). Additional difficulty is caused by performing mathematical analyses of different versions given by the witnesses (e.g.: “he was walking slowly”, “he was walking at a fast pace”), which together with other uncertain data lead to a large number of additional “subversions”. In the paper an analysis of the sensitivity of function describing the kinematics of a pedestrian accident has been made.

In road accident analysis the problem of uncertainty of calculation results becomes essential particularly when modification of input values within the adopted ranges leads to diametric change of the answer to the question posed by the court of justice (e.g. “collision from the right-hand side of the center line” – “collision from the left-hand side of the center line”, or “the accident could have been avoided” – “the accident could not be avoided”). The aim of the paper was to present a method of collision reconstruction calculation using the principle of conservation of momentum, the principle of energy conservation, and the principle of kinetic energy and work equivalence (energy balance) (Marquard), taking into consideration Monte Carlo simulation method. The applicability of the method in determination of distribution function for vehicle collision velocities was proved and, what is more important, its practical uselessness in determination of collision location.

The article presents problems in determining intensive braking parameters from the tachograph chart recordings. A number of braking trials were recorded by a tachograph and a decelerometer simultaneously. Next a comparative analysis of the recordings was performed using both the Siemens VDO method and by electronic processing with commonly available equipment. The first method proved to have limited possibilities for interpretation of the recordings for quantitative determination of intensive braking parameters. The second proved unreliable (with the existing scanner resolution). It has been shown that it is not possible to determine unequivocally the braking time, and consequently the deceleration reached.

In the paper SMASH - a computer program for road accident simulation is presented. Besides the logic of the program the models of vehicle, tire and crash itself are analyzed briefly. Data and diagrams showing the comparison between SMASH results and actual tests data are presented.