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2 Wicher Jerzy

2 2019

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Uncertainty of estimating the length of a maneuver avoiding obstacles on the road

Wicher Jerzy

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

2019

z. 4/122

5--11

Estimation of lengths of maneuver avoiding obstacle depends on values of necessary parameters needed for calculation of the reaction way, the brake way and the way of avoiding obstacle. Little exact estimation of the values of that ways causes large error of calculation. In the paper there are presented different aspects connected with analysis of maneuver and are showed possibility of specifying more precisely results of calculations by using of Monte Carlo method.

Oszacowanie długości drogi manewru omijania przeszkody zależy od wartości parametrów potrzebnych do wyznaczenia drogi reakcji, drogi hamowania i drogi omijania przeszkody. Mało dokładne oszacowanie ich wartości powoduje powstanie dużego błędu wyników obliczeń. W artykule omówiono różne aspekty związane z analizą manewru oraz pokazano możliwość uściślenia wyników obliczeń poprzez zastosowanie metody Monte Carlo.

Reconstruction of the collision of multiple cars considered as the system of material particles

Wicher Jerzy

Archiwum Motoryzacji

2019

Vol. 83, nr 1

123--131

In the situation of high intensity of motor vehicle traffic, collisions or accidents at road intersections often have the form of a collision of multiple cars. The reconstruction of such a road incident is often carried out as an attempt to estimate the velocities of individual cars, especially the velocity of the vehicle that caused the collision. In the analysis of motion of a larger number of vehicles, it may be sufficient to assume that they can be adequately represented by a system of material points with their mass values being known. In such a case, it may be possible to determine the velocity values necessary to assess the safety level and to estimate the degree of responsibility of individual drivers on the grounds of some elementary equations describing a system of material points. The objective of this article is to show, with a collision of three cars being taken as an example, that the determining of the velocity of the vehicle that caused the collision comes down to solving a few simple algebraic equations. Before the reconstruction of a road incident is commenced, data are collected from the incident site. These data constitute the basic sources of evidence. Unfortunately, they may be burdened with a wide uncertainty margin. Therefore, adequate reliability of such data is often decisive for the obtaining of a correct result of the reconstruction. The article shows a possibility of improving the reliability of such data by using relative sensitivity factors to identify the parameters of the road incident under consideration that have the strongest influence on the final calculation result. This means that the values of such parameters should be estimated with the greatest possible accuracy because they have the strongest impact on the uncertainty of assessment of the traffic situation being examined.