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This paper presents the possible use for IR spectroscopy to reveal skid marks left by cars equipped with Anti-lock Braking System. Detailed analysis of literature showed that there is no method that can be used in order to investigate this kind of tire marks. Up till now only two techniques have been devised. The first one is Method of Image Refinement which consists of transforming the image from the scene of the accident using dedicated graphics software. Second method includes analysis of traces using a thermal imaging camera. This study presents an innovative approach to the problem. Numerous analyses using IR spectroscopy were conducted to check the suitability of this method. The research performed on a Thermo Scientific FTIR Nicolet iS50 Spectrophotometer with an ATR attachment. 40 samples from 10 different types of asphalt were prepared. Each sample was measured 3 times to create its spectrum. The results were analyzed thoroughly using the dedicated SpectraGryph software. Analysis show that the wavelength which makes the braking marks visible is found within the mid-infrared range. Finally, it was found wavelength in which skid marks should be visible. This range is located in the mid-infrared.

Detailed analysis of literature showed that there is no method that can be used in order to investigate skid marks left by vehicles equipped with ABS. Authors decided to identify braking trace by using IR spectroscopy. Preliminary studies have been performed and results were promising. Due to that fact authors decided to conduct detailed research where the influence of various factors on the possibility of revealing breaking traces would be taken into account. This article is the first in a series of articles taking into account the influence of various factors on the possibility of revealing breaking marks using IR spectroscopy. In this article the influence of the type of asphalt was studied. Authors conducted tests with the most popular types of asphalts used for the wearing course. 100 samples from 5 different types of asphalt were prepared. Each sample was measured 3 times to create its spectrum. The results were analyzed thoroughly using the dedicated SpectraGryph software. The analysis showed that for 4 out of 5 types of tested asphalt, the braking traces were visible at a wavelength of approximately 11 500 nm. Only for the rubberized asphalt there weren’t possibility to reveal skid mark.

Presented paper discusses two different nonlinear approaches to precrash velocity determination for vehicles from Intermediate Car Class. Data that was used to perform analyses introduced in this paper was taken from National Highway Traffic Safety Administration (NHTSA) database. Such database is comprised of substantial number of crash cases and main focus was put on frontal impacts. Hitherto used energy methods are based on linear model which proves to be inaccurate and producing significant errors. Presented considerations concern the inverse system and tensor product of Legendre polynomials. The focus of those methods is to establish the value of nonlinear coefficient which is the slope factor of precrash velocity Vt and deformation ratio Cs function. The application of the least square method provides more precise results in both cases than in previously researched solutions, with a slight advantage of the tensor product method. The obtained mean relative error of the velocity determination using the inverse system method is approximately 16,22% for the linear model and 10,58% for the nonlinear model. In the case of the tensor product method the errors for linear and nonlinear models are respectively 6,74% and 6,3%.

A new non-linear method utilizing the work W of car deformation is considered in this study. The car deformation is defined as an algebraic function of deformation ratio Cs. The method of variable correlation is exploited in order to develop experimental data. To determinate mathematical model parameters, data from the NHTSA database including frontal crash tests are used. Such database is comprised of substantial number of crash cases and main focus was put on frontal impacts. In the non-linear method used so far, the so-called energetic approach, collisions are considered non-elastic. The speed threshold defining the elastic collision was set to be 11 km/h. This simplistic approach is used to determine the linear relation of energy loss during deformation on deformation coefficient Cs. Deformation points C1-C6 are taken into account while calculating a mean value that defines this coefficient. A more accurate non-linear method as well as more complex form of deformation coefficient is suggested to determine the work of deformation in this paper. The focus of those methods is to establish the value of nonlinear coefficient b_k which is the slope factor of precrash velocity Vt and deformation ratio Cs function.