Application of ТАSolver software package in the study of circumstances of traffic collisions that occurred in conditions of limited visibility

The article purpose is to improve the quality of examinations and expert studies, reduce export’s labor costs, as well as increase the probative value of an expert’s opinion which will be facilitated by the use of ТАSolver software package for the study of traffic collisions that occurred in conditions of limited visibility.

Florin Rusitoru, Oleksandr Sviderskyi, Vitalii Varlahov. Application of ТАSolver software package in the study of circumstances of traffic collisions that occurred in conditions of limited visibility. DOI: 10.32353/khrife.3.2021.08 115 The article purpose is to improve the quality of examinations and expert studies, reduce export's labor costs, as well as increase the probative value of an expert's opinion which will be facilitated by the use of ТАSolver software package for the study of traffic collisions that occurred in conditions of limited visibility.
Keywords: road accident analysis; traffic collision; study; limited visibility; vehicle; software package; collision; graphic-analytical method.

Research Problem Formulation
One of the main issues facing road-accident analysis during the investigation of traffic collisions (hereinafter referred to as TC) is the issue of whether a driver has technical ability to prevent a collision. The solution of this issue involves establishing the distance at which the vehicle was (hereinafter referred to as Vehicle) from the place of collision at the time of danger for further movement. Determining the distance during the investigation of TC that occurred in conditions of limited visibility is a complex process and differs from similar situations in conditions of unlimited visibility as it involves investigative actions at the scene of TC with every second movement of Vehicles and pedestrians or several Vehicles from the place of the collision taking into account their speeds. This method involves the use of calculations to determine the distances covered by Vehicles and pedestrians or several Vehicles over a period of time. In the future, the participants of TC are moved from the position in which they were at the time of the collision to the position in which they had been at the time when the driver saw a pedestrian or other Vehicle because of the object that restricts visibility. The distance can also be determined by creating a graphic-analytical model based on the initial data set by the investigator.

Analysis of Essential Researches and Publications
The application of the graphic-analytical method of determining the distance in the process of conducting road-accident analysis in their works is considered by V.

The Article Purpose
To improve the quality of examinations and expert research, reduce the labor costs of the expert for conducting expert research, as well as increase the probative value of the expert's opinion.

Main Content Presentation
The graphic-analytical method of studies is universal and has a number of advantages as it allows to establish the relative position of the Vehicle and pedestrian or several Vehicles at different moments of time and provides visibility of results (in particular, intermediate with the pedestrian and coordinates of this place relative to the boundaries of the carriageway, breaking marks, the place of the pedestrian's exit on the carriageway; brand of Vehicle and speed of its movement; pedestrian speed; the distance over which the Vehicle was moving that collided relative to the boundaries of the carriageway; coordinates of the driver's location of the Vehicle that crashed; the distance from the rear or front of the Vehicle, which limited visibility, to the pedestrian at the time of his exit to the carriageway; the distance from the boundaries of the carriageway to the Vehicle, which limited visibility, or the lateral interval between several Vehicles. Prior to implementation of computer equipment and software engineering into an expert practice, the relative position of Vehicles and pedestrians at certain intervals was determined by experts using creating graphic-analytical construction (most often -graphical construction on a scale diagram). Today there are many software packages that allow modeling a mechanism of TC development at different stages (V-SIM, PC-crash, CARAT, etc.). These software packages are complex licensed prod-Florin Rusitoru, Oleksandr Sviderskyi, Vitalii Varlahov. Application of ТАSolver software package in the study of circumstances of traffic collisions that occurred in conditions of limited visibility. DOI: 10.32353/khrife.3.2021.08 117 ucts designed to simulate TC, problem situations on the road, simulation of Vehicle contact, and other participants in TC. Due to the complexity of use, these packages are not always acceptable when solving local road-accident analyses to determine the parameters (initial data) of the TC mechanism (e.g., to set parameters of the Vehicle or Vehicle and pedestrian, provided that one of the TC participants appears due to object that limits visibility).
In order to simplify the solution of such issues specialists of National Scientific Center «Hon. Prof. M. S. Bokarius Forensic Science Institute» developed TASolver software package which allows to quickly and easily simulate the situation of TC with the appearance of danger due to the object that limits visibility. This software package is used to determine the relative position of several Vehicles or Vehicle and the pedestrian at different times in the presence of relevant initial data with the result in graphic format, as well as calculations of stopping (S o ), time of movement of Vehicle in the braked state until collision (t' Т ), and distance (S a ). The results of the study can be saved in ".tas" format for further work during the preparation of the expert's opinion.
TASolver software package makes it possible to determine the location of Vehicle in relation to the place of collision in conditions of limited visibility by the driver through the object that may be temporarily immovable (restriction of visibility through another Vehicle moving in the cross direction), stationary (a house, fence, etc.) or movable (restriction of visibility due to a pedestrian moving on the carriageway for the driver of one Vehicle to another Vehicle moving in the opposite or passing direction).
TASolver software package allows to display the results of calculations on the monitor screen and graphical constructions in two languages (Russian and Ukrainian), as well as perform graphical constructions in the scale selected by the user. It has a database of vehicles that can be fulfilled with Vehicles with new technical parameters.
After launching the program, the dialog box displays the title, menu bar, toolbar, work area ( fig. 1). The menu bar provides access to program features that allow opening, saving, printing files, selecting research options (movable or immovable obstacle), as well as editing the title, and changing the language. Some program features are displayed on the toolbar (in particular, change the scale (possible scales 1 : 100, 1 : 150, 1 : 200, 1 : 250), display the dimensions of Vehicles, change the print format (А3, А4)). The work area has the form of an empty where the results of studies will be displayed in the future (the printing area is marked with a dotted line).
Let's consider various examples of determining the distance for TC that occurred under conditions of limited visibility using TASolver software package.

1st example
Visibility of the pedestrian crossing the carriageway from right to left in relation to the direction of movement of Vehicle-1, limits the Vehicle-2, which moves on the opposite side. It is necessary to establish the distance at which Vehicle-1 was at the time of the pedestrian in the driver's field of vision due to accompanying Vehicle-2. The accident occurred under the following road conditions and circumstances: • asphalt concrete carriageway, dry, horizontal profile, for one direction of movement, 12.0 m wide; • Vehicle-1 (Lexus), moving at the speed of 50 km/h, the distance from the right gauge to the right edge of the carriageway -5.5 m; • Vehicle-2 (Mercedes Vito), moving at the speed of 30 km/h, the distance from the right side of the Vehicle-1 to the left side of the Vehicle-2 -2.0 m; • direction of the pedestrian's movement -from right to left (relative to the direction of movement of the Vehicle-1), from the moment of exit to the carriageway to the moment of collision, the pedestrian covered a distance of 6.0 m in 2.8 s; • before collision Vehicle-1 and Vehicle-2 were moving without braking and maneuvering. First, in the "Settings" menu bar you should choose: Obstacle → Movable. Then the "Parameters" dialog box appears, in which the initial data is entered according to the given instructions ( fig.2). The initial data section of the dialog box is divided into four zones: Vehicle-1, Vehicle-2, Pedestrian, Road. After entering the data, characterizing the specific situation of TC, to calculate and build the graphical scheme you should click "Calculate". The program calculates parameters of the relative position of the Vehicles-1, Vehicle-2, and pedestrian at the time when the pedestrian went on the carriageway, as well as at the moment when the pedestrian appeared in the field of view of the driver of Vehicle-1 due to the Vehicle-2. Calculations will be displayed in the dialog box "Parameters" (Fig. 4), after closing which in the work area will form a graphical diagram depicting the Vehicle-1, Vehicle-2, and pedestrians at the above points.
During the study to the given initial data it was established: the drive of Vehicle-1 could not see the moment of the pedestrian's exit to the carriageway as visibility of the pedestrian was limited by Vehicle-2; at the moment of pedestrian's exit to the carriageway Vehicle-1 was from a place of collision on the distance of 38,89 m (S a1 ); stopping distance of Vehicle-1 -35,12 m (S o ); Vehicle-1 was at the distance of 26,93 m from the place of collision at the time of appearance of the pedestrian in the driver's field of vision due to the accompanying Vehicle-2 (S ВП ). Also, on the graphical scheme the time of pedestrian's movement from the moment of his exit to the carriageway until the moment of appearance in the field of view of the driver of the Vehicle-1 (Fig. 5).
Capabilities of TASolver program also include research for the following TC situations: • when the collision with the pedestrian occurred during the movement of Vehicle-1 in a braked state (for this purpose in the data area "Vehicle-1" in the window S'' т or S' ю you should indicate the distance covered by the Vehicle-1 before the collision in braked condition, or the length of braking trace from the moment of its display to the moment of collision); • when the pedestrian gets out of immovable "Vehicle-2" (in this area of initial data "Vehicle-2" in the window V a2 it is necessary to specify the speed of 0 km/h); • if the Vehicle-2 moves in the opposite direction (in the area of initial data "Vehicle-2" it is necessary to indicate the direction of movement of the Vehicle-2 "Towards the Vehicle-1"); • when the pedestrian crosses the carriageway at the angle (in the area of initial data "Pedestrian" it is necessary to indicate the movement of the pedestrian relative to the Vehicle-1 (incidentally, right, oncoming, left); • when the collision of Vehicle-1 with the pedestrian occurred on the side (it is necessary to establish the distance from the front of Vehicle-1 to the point of contact with the pedestrian L х1 ). In addition, with the help of TASolver program, it is possible to investigate TC that occurred in conditions of limited visibility through an immovable stationary object (a house, fence, etc.). To solve this task, first in the "Settings" menu bar you should choose: Obstacle → Immovability. Then the "Parameters" dialog box appears, in which the initial data is entered according to the given instructions (Fig. 6).

nd example
TC occurred at the crossroad in conditions of limited visibility, namely: visibility of Vehicle-2 to the driver of Vehicle-1 is limited to an immovable stationary object (the fence). It is necessary to establish the distance at which Vehicle-1 was at the time of Vehicle-2 in the driver's field of vision due to the object that limited visibility. The incident occurred under the following road conditions and circumstances: • unequal crossroad, asphaltconcrete carriageways, dry, horizontal profile, each for the movement of Vehicles in one direction, the carriageway in the direction of traffic Vehicle-1 width -8.0 m, in the direction of traffic Vehicle-2 -6.0 m;

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• Vehicle-1 (Lexus) moved at the speed of 60 km/h at a distance of 2.0 m from the right edge of the carriageway and 6.0 m from the object which limits visibility; • Vehicle-2 (Mercedes Vito) moved at the speed of 40 km/h at a distance of 2.0 m from the left edge of the carriageway and 8.0 m from the object which limits visibility; • direction of the movement of Vehicle-2 from right to left relative to the movement of the Vehicle-1; • direction of the movement of Vehicle-1 from left to right relative to the movement of the Vehicle-2; • before collision Vehicle-1 and Vehicle-2 moved in an unbraked state without maneuvering. The initial data characterizing the specific situation of TC is entered into the dialog window of the program (Fig. 7). To perform calculations and build the graphical scheme you should click "Calculate".
The program will graphically display the relative position of Vehicle-1 and Vehicle-2 at the time of Vehicle-2 in the field of view of the driver of Vehicle-1 due to the immovable obstacle that limits visibility (Fig. 8).
Conducting research on the given initial data allowed to establish: at the moment of appearance of Vehicle-2 in the field of view of the driver of Vehicle-1 due to immovable stationary object Vehicle-1 was at a distance of 16.83 m (S а1 ); at that time Vehicle-was at a distance of 12,56 m from the collision place (S а2 ).
The graphic diagram also shows the time of movement of Vehicle-2 in the field view of the driver of Vehicle-1 before the collision (Fig. 8).
The capabilities of TASolver program also include research for TC when the collision occurred during the movement of Vehicle-1 and Vehicle-2 (or one of them) in a braked state. To do this, in the area of initial data "Vehicle-1" or "Vehicle-2" in the window S' ю it is necessary to specify the length of the braking trace from the moment of its display to the collision.

Conclusions
The given examples of TC studies, which occurred in conditions of limited visibility, show that the use of TASolver software package developed by specialists of National Scientific Center «Hon. Prof. M. S. Bokarius Forensic Science Institute» helps to improve the quality of studies, reduces the labor costs of the expert to conduct examinations, as well as increases the probative value of the expert's opinion.