Definition of a blocking blow crash. Vehicle collision mechanism. Classification of traffic accidents

Primers 14.11.2020

Primers

The main types of accidents that require ACR are collisions, which are divided into:

windshield- vehicle collision in oncoming traffic;

lateral- collision of the vehicle with the side of another vehicle;

tangent- collision of the vehicle with the sides in the oncoming traffic or movement in one direction;

overturning- an incident in which a moving vehicle overturned;

hitting a parked vehicle- an incident in which a moving vehicle ran into a stationary vehicle, as well as a trailer or semi-trailer;

hitting an obstacle- an incident in which the vehicle ran over or hit an immovable object (bridge support, pole, tree, fence, etc.).

Special types of accidents that require an ACP

Special types of accidents- road accidents complicated by dangerous factors that require special training of rescuers or the involvement of additional forces and means.
Accident with vehicle falling into water- accidents in which the vehicle falls into rivers, lakes, the sea for some reason, falls through the ice, etc.
Accident with vehicle falling down steep slopes- accidents in which the vehicle for some reason breaks off steep slopes and, as a rule, rolls over several times, hitting rock ledges, and flies 100-150 m or more. Sometimes vehicles explode. The vehicle itself turns into a pile of twisted metal.
accident on site railway - road accidents, in which: the vehicle collides with a rolling or stationary train at a railway crossing or on a section of the railway not intended for crossing; A vehicle collides with another vehicle at a railroad crossing; a rolling stock runs into a vehicle at a railway crossing or on a section of the railway not intended for crossing.
Accident involving a tram (trolleybus)- Accidents in which a tram (trolleybus) collided (hit) another vehicle, or as a result of a break and fall of power wires on the vehicle, or a tram derailment and overturning, the vehicle or people were injured.
Accident with fire- an accident accompanied by the ignition of emergency vehicles and the goods they carry.
Hit of the vehicle under the rubble- an accident in which a vehicle with people as a result of natural or man-made phenomena fell under an avalanche, mudflow, landslide, rockfall, etc.
Accident in a tunnel (overpass)- road accidents complicated by the specifics of a limited space, which makes it difficult to access the site of an accident, carry out ACP and evacuate victims.
Accident with a vehicle carrying dangerous goods- an accident with a vehicle carrying cargo that falls under the category of hazardous, as a result of which its leakage (emission, fire, etc.) occurred or there is a danger of such a situation, including:
- an accident with a vehicle carrying combustible (FL) or flammable liquids (FLL), as a result of which they spilled or leaked;
- an accident with a vehicle carrying emergency chemically hazardous substances (AHOV), as a result of which they spilled or leaked;
- an accident with a vehicle carrying radioactive substances (RS), as a result of which they spilled or leaked, resulting in contamination with them environment;
- an accident with a vehicle carrying biologically hazardous substances (BV), as a result of which they spilled or leaked, resulting in contamination of the environment;
- an accident with a vehicle carrying explosives and explosive items, in which there was a threat of detonation of explosives and explosives due to their movement, mechanical impact on them or heating (burning).

The bodywork is designed to withstand the impact of normal driving and to ensure the safety of passengers in the event of a vehicle collision. When designing the body, special attention is paid to ensuring that it deforms and absorbs the maximum amount of energy in a serious collision, while at the same time having a minimum impact on passengers. For this purpose, the front and rear parts of the body must be easily deformed to a certain extent, creating a structure that absorbs impact energy, and at the same time, these parts of the body must be rigid in order to preserve the separation area for passengers.

Vehicle collision

Typical damage to the vehicle and typical injuries of the injured in a tangential collision No. Type of accident Typical damage to the vehicle Typical injuries of the injured 1 Tangential collision Deformation of the contacting sides of the vehicle, jamming broken glass abdominal trauma, chest, faces, rib fractures, cut-stab, lacerated wounds. 2.3. Work Performance Technology Vehicle Stabilization A set of support blocks and pneumatic jacks is used to stabilize the vehicle.
Wedges and blocks made of plastic and wood of the vehicle remained on the roadbed with support on all wheels, therefore, to stabilize the vehicle, it is necessary to install support blocks and put wedges under the wheels. Disconnecting the battery If it is impossible to get direct access to the battery of a car, it is necessary to open the hood of the vehicle using an extender.
If it is impossible to disconnect the battery, the power wires are cut off near the terminals.

Technological map No. 2

Attention

On this basis, collisions are divided into: 1. Central - when the direction of the collision line passes through the center of gravity of the vehicle. 2. Eccentric - when the collision line passes at some distance from the center of gravity, to the right (right eccentric) or to the left (left eccentric) of it.

VI. At the point of impact. On this basis, collisions are divided into: 1. Frontal (frontal) - a collision in which traces of direct contact upon impact with another vehicle are located on the front parts.
2.

Front corner right and front corner left - a collision in which contact marks are located on the rear and adjacent sides of the vehicle. 3. Side right and side left - a collision in which the blow was delivered to the side of the vehicle.

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AFM no more than 7 Assessment of the condition of the injured and the vehicle Visually up to 1 Designation of working areas Reflective cones, signal tape, fire extinguisher 1-2 Vehicle stabilization Support blocks and wedges 2 Opening the vehicle hood and disconnecting the battery Expander, wire cutters 1-2 Protecting the driver and passengers from splinters glass, windshield removal, shutdown of failed systems air cushions safety and release of victims from seat belts Tarpaulin, glass breaker, wire cutters, knife for cutting seat belts 2-3 Release of victims: dismantling of doors, B-pillars, front and rear pillars, removal of the roof Expander, wire cutters, single- and double-rod cylinders 15-20 Providing first aid kit to the injured First aid kit PP, neck brace 4-5 Removal of the injured from the vehicle Evacuation shield, stretcher 2-3 Delivery of the injured to the ambulance Evacuation shield, stretcher 1-2 Notes: 1.

The most typical example is a collision during lane change, when the driver, before performing the maneuver, was not convinced that there were no vehicles in the immediate vicinity moving in the adjacent lane in the same direction. Such road accidents lead to serious consequences when a large vehicle becomes one of the participants in the accident (for example, a large bus “pressed” a passenger car or a motorcyclist).

In most cases, the case is limited to not the most severe damage to vehicles. The driver who performed the rebuilding is recognized as the culprit of the accident.

Rear collisions are the result of failure to maintain a safe distance by the driver of a vehicle moving behind another vehicle.

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After gaining access to the victims and conducting a preliminary examination, provide them with first aid, including immobilization of the spine. 8. Evacuation of the injured and their transfer to the ambulance team.

Operations 1-5 are carried out by rescuers simultaneously. Notes: - it is best to approach the vehicle from the front. In this case, victims who are conscious will not try to turn their heads to establish contact with rescuers, which may worsen their condition in case of a spinal or head injury; - if the battery cannot be disconnected, turn on the alarms as a warning to other rescuers; - it is necessary not to remove the victims from the vehicle, but to disassemble the elements of the damaged vehicle around the victims until they are released.
2.2.

Section 31 Car Collision

Collision theory To understand the scale of car damage after an accident, one must clearly understand what happens directly at the moment of impact with the car body, which areas are subject to deformation. And you will be unpleasantly surprised to know that in a frontal impact, the rear of the body is skewed.

Accordingly, after an unscrupulous body repair of the front, even if the car was on the slipway, you will observe the jamming of the trunk lid, chafing of the sealing gum, and much more. If you are interested in this topic, I suggest that you familiarize yourself with educational material on the theory of collisions, which was prepared by the specialists of our training center.

Background Collision theory is the knowledge and understanding of the forces generated and acting in a collision.

Examples of the main types of vehicle collisions:

Important

In this case, as a rule, an abrupt stop of the vehicle occurs and, as a result, a dynamic impact of great force occurs. The collision can occur with any part of the vehicle.

Info

Tipping. It occurs as a result of a side impact, a sharp turn, the exit of the vehicle into areas with a large transverse steepness. A rollover causes the vehicle to fall on its side or roof.

Quite often it leads to significant deformations of the body, pinching or blocking people in the cabin, their falling out and pressing to the ground, spilling fuels and lubricants. Best sayings: For students, there are even, odd and credit weeks.

Classification of traffic accidents

Transverse - a collision in which the projection of the velocity vector of one vehicle onto the direction of the velocity of the other is O (the angle α is 90; 270 degrees). III. According to the relative arrangement of the longitudinal axes of the vehicle.

The sign is determined by the angle of mutual arrangement of their longitudinal axes. On this basis, collisions are divided into: 1. Direct - a collision with a parallel arrangement of the longitudinal or transverse axis of one vehicle and the longitudinal axis of the second vehicle (angle α is 0; 90 degrees).

Oblique - a collision in which the longitudinal axes of the TC' were located relative to each other under acute angle; (angle α is not equal to 0; 90 degrees). IV. By the nature of the interaction of the vehicle upon impact. The sign is determined by deformations and traces in the contact areas.

On this basis, collisions are divided into: 1.

collision theory

In this zone, there are emergency rescue tools, equipment and devices necessary for carrying out the ACP, as well as a platform for storing dismantled parts from the damaged vehicle when the victims are released. Work areas are marked with reflective cones or signal tape.

2.1. General order actions of rescuers in this type of accident 1. Establish and constantly maintain contact with the victims, if they are conscious. 2. Designate the areas of ACP. 3. Inspect the scene of the accident around the vehicle and the space under them. 4. Stabilize vehicles to prevent them from moving during work. 5. Turn off the ignition systems of the vehicle and disconnect the batteries (batteries). 6. Carry out work to release the victims and release them from seat belts.

Works on unblocking the victims Removing glass To access the victims for the purpose of their initial examination, with jammed doors, it is necessary to break the glass with a cullet. Victims should be covered with tarpaulin, which will protect them from flying fragments.

Opening, removing doors and dismantling the roof In this type of accident, in order to create access to provide assistance to victims or for their immediate evacuation (if necessary), the doors are dismantled from both sides of the car. The middle racks have a snack in two places (top and bottom).

The front and rear pillars are cut, the roof is dismantled. Shift (raise) of the dashboard The shift of the dashboard of the car is carried out to facilitate the evacuation of the victims or gain access to their legs.

Tangential collision during an accident

Collisions Collisions are the most common type of accident. Collisions are frontal, side, tangent, rear.

The most dangerous of these are head-on collisions: this happens with vehicles moving in opposite directions when one of the drivers violated the Rules traffic(for example, violation of the rules of overtaking). characteristic feature head-on collisions is that they very often lead to death or serious injuries and injuries to people. Side collisions often occur at intersections when one of the drivers did not give way in the right place, or drove through a prohibitory traffic light, etc. Tangential collisions typically occur between vehicles traveling in the same direction.

The location of damage to the vehicle from contact with each other makes it possible to determine their relative position at the moment of collision and clarify the place of collision if the location and direction of movement of one of them at the moment of collision are established.

Sometimes the angle is determined from photographs of damaged vehicles. This method gives good results only when pictures of different sides of the car are taken at right angles from the same distance. Due to the fact that carrying out measurements of vehicle deformation and taking photographs to determine the angle of collision requires certain skills and knowledge, it is advisable to carry them out with the participation of experts.

The direction of deformations, which determines the direction of the impact, allows you to set the possible displacement of the vehicle from the place of collision, and by its location after the accident, to clarify the place of the collision.

The nature of the deformations makes it possible to set the collision angle of the vehicle and by calculation to determine the value of the interval between the moving parallel courses of the vehicle before turning one of them onto the lane of the other (based on the maximum adhesion of the turning radius). This allows you to specify the location of the collision according to the width of the lane.

Rice. 4. Types of location of vehicles at the time of the accident.

The location of damages on the lower parts of the vehicle, which left tracks on the road during a collision, makes it possible to clarify the position of the vehicle by the width of its lane when these tracks were formed at the collision site.

The study of damage to painted and metal parts allows you to establish the direction of movement of colliding vehicles. Marks on the surface of a damaged car that are wider than deep and longer than wide are called scratch marks. The scratches run parallel to the damaged surface. They have a small depth and width at the beginning, expanding and deepening towards the end. If the primer is damaged along with the paintwork, then it exfoliates in the form of wide, drop-shaped scratches, 2-4 mm long.

Damage that is deeper than the width is called scuffing and denting. The depth of the scratch usually increases from its beginning to the end, which makes it possible to determine the direction of movement of the scratched object. Sharp burrs often remain on the surface of the scuff, which are bent in the same direction in which the scratching object moved. The slower car has scratch marks from the back to the front, while the overtaking car has the opposite direction.

In a head-on collision, the speeds of the cars cancel each other out. If their mass and speed were the same, then they stop near the collision site. If the masses and speeds were different, then the car moving at a lower speed or lighter is thrown back. In the event that the driver of a truck at the time of an accident does not take his foot off the gas pedal and, confused, continues to press it, then the truck can drag an oncoming passenger car a fairly long distance from the collision site.

The classification of vehicle collision types, which meets the needs of autotechnical expertise, should contribute to the selection of methods and the most complete development of a methodology for expert study of the circumstances that determine the collision mechanism.

The classification of types of collisions is shown in Figure 2.1.

Figure 2.1 - Classification of vehicle collision types

To common features the following belong:

1 Movement of one vehicle in a transverse direction with respect to the lane of another in the process of their approach (classification in the direction of movement of the vehicle). The sign is determined by: the value of the collision angle b, which can be established by the tracks of the wheels of both vehicles before the collision, by the location of the vehicle and the traces of their movement after the incident, by the direction of throwing objects separated from them (glass fragments, etc.), by the deformations obtained during the collision .

On this basis, collisions are divided into 2 groups:

a) longitudinal - collision without relative displacement of the vehicle in the transverse direction, i.e. when moving them in parallel courses (the angle b is equal to 0 or 180 °);
b) cross collision - a collision when the vehicle is moving in non-parallel courses, i.e. when one of them was displaced in the transverse direction towards the lane of the other (the angle b is not equal to 0 or 180 °);
2 Movement of the vehicle in the longitudinal direction relative to each other (classification according to the nature of the mutual approach of the vehicle). The sign is also determined by the value of the collision angle b.

On this basis, collisions are divided into three groups:

a) head-on - a collision in which the projection of the velocity vector of one vehicle onto the direction of the velocity of another vehicle is opposite to this direction; The vehicles approached each other with a deviation towards each other (angle δ > 90°,
b) passing - a collision in which the projection of the velocity vector of one vehicle onto the direction of the velocity of another coincides with this direction; The vehicles approached, shifting with a deviation in one direction (angle 6
c) transverse - a collision in which the projection of the velocity vector of one vehicle onto the direction of the velocity of the other is zero (angle b is 90º, 270°).

If the angle δ differs so little from zero or from 90° that the methods of investigation used do not allow us to establish this deviation, and if the possible deviation does not have a significant effect on the collision mechanism, then the latter can be defined as longitudinal or transverse, respectively.

3 Relative arrangement of the directions of the longitudinal axes of the vehicle at the time of the collision. The sign is determined by the angle of mutual arrangement of their longitudinal axes 60, which is established on the basis of trace studies of traces and damages in the places of direct contact of the vehicle during a collision. In some cases, the angle 60 can be set according to the tracks of the wheels in front of the collision.

a) direct - a collision with a parallel arrangement of the longitudinal or transverse axis of one vehicle and the longitudinal axis of the other (the angle 60 is equal to 0.90?);
b) oblique - a collision in which the longitudinal axes of the vehicle were located relative to each other at an acute angle (the angle 60 is not equal to 0.90?).
4 The nature of the interaction of the contacting sections of the vehicle during the collision. The sign is determined by deformations and traces in the contact areas.

On this basis, collisions are divided into groups:

a) blocking - a collision in which, in the process of contacting, the relative speed of the vehicle in the contact area by the time the deformations are completed decreases to zero (the translational speeds of the vehicle in this area are equalized). With such a collision, in addition to dynamic, static traces (imprints) remain on the contact areas;
b) sliding - a collision in which in the process of contact slippage occurs between the contacting areas due to the fact that until the moment the vehicle leaves contact with each other, the speeds do not equalize. In this case, only dynamic traces remain on the contact areas.
c) tangential - a collision in which, due to the small amount of overlap of the contacting parts of the vehicle, only insignificant damage is received and continues to move in the same directions (with a slight deviation and a decrease in speed). In such a collision, horizontal tracks remain on the contact areas (scratches, abrasions). An accident is not a consequence of the forces of interaction upon impact, but the subsequent collision with other obstacles.
5 The direction of the vector of the resultant of the shock impulse vectors (direction of the collision line) in relation to the location of the center of gravity of this vehicle, which determines the nature of its movement after the collision (with or without a turn). On this basis, collisions are divided into 2 groups:
- a) central - when the direction of the collision line passes through the center of gravity of the vehicle;
- b) eccentric - when the collision line passes at some distance from the center of gravity, to the right (right eccentric) or to the left (left eccentric) of it.
6 Location along the perimeter of the vehicle of the area that was in contact during the impact (classification according to the location of the impact). The sign (along with the angle of relative position 60) determines the mutual position of the vehicle at the time of the collision.

On this basis, collisions are divided into the following groups:

a) frontal (frontal) - a collision in which traces of direct contact upon impact with another vehicle are located on the front parts;
b) front corner right and c) front corner left - a collision in which contact traces are located on the front and adjacent side parts of the vehicle;
d) lateral right and e) lateral left - a collision in which the blow was delivered to the side of the vehicle;
f) rear corner right and g) rear corner left - a collision in which traces of direct contact are located on the rear and adjacent side parts of the vehicle;
h) rear - a collision in which contact traces resulting from the impact are located on the rear parts of the vehicle.

Such a classification system of types of collisions makes it possible to cover all possible types of two or more collisions of the vehicle and formalize the characteristics of any collision.

Depending on the need, a collision may not be characterized by all classification criteria, but only by some of them. Other classification groups may be included in the intended classification system, depending on the purpose of the classification.

The possibility of resolving the issue of the place of collision of the vehicle by expert means and the accuracy with which it is possible to determine the location of each vehicle on the road at the time of the collision depend on what initial data the expert has on the circumstances of the accident and how accurately this place is determined.

To determine or clarify the location of the vehicle at the time of their collision, the expert needs the following objective data:

About the traces left by the vehicle at the scene of the incident, about their nature, location, length;

About traces (tracks) left by objects thrown off during a collision: parts of the vehicle that separated during impact, cargo that fell out, etc.;

About the location of areas of accumulation of small particles that have separated from the vehicle: earth, dirt, glass fragments, areas of splashing liquids;

About the location after the collision of the vehicle and objects discarded during the collision;

About vehicle damage.

In most cases, the expert has only some of the listed data.

It should be noted that, no matter how conscientiously the situation at the scene of an accident is recorded by persons who do not have experience in conducting auto technical examinations (or do not know the methodology of expert research), omissions cannot be avoided, and they often make it impossible to determine the location of the collision. Therefore, it is very important that the inspection of the scene was carried out with the participation of a specialist.

When examining and examining the scene of an accident, first of all, it is necessary to record those signs of an accident that may change during the inspection, for example, signs of braking or skidding on a wet surface, signs of movement of small objects, tire marks left when driving through puddles or leaving roadsides, patches of sprinkled ground during rain. The location of the vehicle should also be recorded if it is necessary to move them to provide assistance to the injured or to clear the roadway.

Determination of the place of collision on the tracks of vehicles

The main signs by which you can determine the place of the collision are:

A sharp deviation of the wheel track from the initial direction, which occurs during an eccentric impact on the vehicle or when it hits its front wheel;

Lateral displacement of the trail resulting from a central impact and an unchanged position of the front wheels. With a slight transverse displacement of the trace or its slight deviation, these signs can be detected by examining the trace in the longitudinal direction from a low height;

Side slip marks of unlocked wheels are formed at the time of a collision as a result of the lateral movement of the vehicle or a sharp turn of its front wheels. As a rule, such traces are hardly noticeable.

Termination or rupture of the trace of the user. Occurs at the time of a collision due to a sharp increase in the load and violation of the wheel lock or separation from the road surface;

The skid mark of one wheel that was hit jammed it (sometimes only for a short period of time). In this case, it is necessary to take into account in which direction this trace was formed, based on the location of the vehicle after the incident;

Traces of friction of vehicle parts on the coating during the destruction of its running gear (when the wheel is torn off, the suspension is destroyed). They begin mainly near the collision site;

Traces of movement of both vehicles. The place of collision is determined by the intersection of the directions of these traces, taking into account the relative position of the vehicle at the time of the collision and the location of the parts on them that left traces on the road.

In most cases, the listed signs are hardly noticeable, and when examining the scene of the incident, they are often not recorded (or not recorded accurately enough). Therefore, in cases where the exact location of the collision is essential to the case, it is necessary to conduct an expert study of the scene.

Determining the collision location from traces left by discarded objects

In some cases, the location of the collision can be determined by the direction of the tracks left on the road by objects thrown off during the collision. Such tracks can be scratches and successively located holes on the road left by parts of the vehicle, motorcycles, bicycles or cargo that has fallen, as well as traces of dragging the bodies of drivers or passengers who fell out of the vehicle at the time of impact. In addition, traces of the movement of small objects, visible on snow, soil, dirt, dust, remain at the scene of the incident.

First, the objects that are thrown away move in a straight line from the place of their separation from the vehicle. Subsequently, depending on the configuration of the object and the nature of its movement on the road surface, a deviation from the original direction of movement may occur. In pure sliding, on a flat surface, the movement of objects remains almost straight to a stop. When rolling in the process of movement, the direction of movement may change as the speed decreases. Therefore, the place of collision of the vehicle can be determined by the traces of discarded objects, if there are signs that these objects were moving in a straight line or the trajectory of their movement is visible.

To determine the location of the vehicle at the time of the collision, following the traces of thrown objects in the direction of the probable collision site, lines should be drawn - continuation of the direction of these traces. The place of intersection of these lines corresponds to the place of impact (the place of separation from the vehicle of objects that left traces).

The more traces left by discarded objects are recorded, the more accurately it is possible to indicate the collision location, since it becomes possible to select the most informative traces by discarding those that could deviate from the direction to the collision site (for example, when objects were rolled, which left them, while moving objects through irregularities, with the location of the beginning of the trace at a great distance.

Determination of the collision site by the location of objects separated from vehicles

It is impossible to find out the place of collision of the vehicle by the location of any parts, since their movement after separation from the vehicle depends on many factors that cannot be ignored. The location of the maximum number of parts discarded during the collision can only approximately indicate the location of the collision. Moreover, if the collision site is determined by the width of the road, it is necessary to take into account all the circumstances that contributed to the unilateral displacement of the discarded parts in the transverse direction.

A fairly accurate place of collision is determined by the location of the earth, which crumbled from the lower parts of the vehicle at the time of impact. In the event of a collision, earth particles fall off at high speed and fall onto the road almost at the point where the impact occurred.

The greatest amount of earth is separated from the deformed parts (surfaces of the wings, mudguards, bottom of the body), but if the car is very dirty, the earth can crumble from other areas. Therefore, it is important to determine not only from which particular vehicle the earth crumbled, but also from which parts of it. This allows you to more accurately indicate the location of the collision. In this case, the boundaries of the areas of shedding of the smallest particles of earth and dust should be taken into account, since large particles can move further by inertia.

The location of the collision can be determined by the location of the debris scattering areas. At the moment of impact, fragments of glass and plastic parts scatter in different directions. It is difficult to determine with sufficient accuracy the influence of all factors on the movement of fragments; therefore, it is possible to indicate the place of impact only by the location of the dispersion area (especially if it is of considerable size) approximately.

When determining the collision site by the location of the debris in the longitudinal direction, it should be taken into account that the debris in the direction of movement of the vehicle is scattered in the form of an ellipse, the nearest edge of which passes from the impact site at a distance close to the place of their movement in the longitudinal direction during free fall. This distance can be determined by the formula:

where,

Va - vehicle speed at the moment of glass breakage, km/h;

h is the height of the lower part of the broken glass, m.

As a rule, the smallest fragments, debris large sizes can move much further, moving on the road surface after a fall due to inertia.

By the location of small debris, the collision location is more accurately determined on a wet, muddy, dirt road or on a road with gravel, when slipping of small debris on the road surface is difficult.

In head-on collisions, the impact site in the longitudinal direction can but an example but to determine based on the location of the far boundaries of the areas of dispersion of glass fragments rejected from each of the vehicles colliding in the direction of its movement. With a similar nature of the destruction of the same type of glass, the maximum distance of debris ejection when they move along the road surface is directly proportional to the square of the speed of the vehicle at the time of the collision (Fig. 1). Therefore, the collision site will be located at such a distance from the far boundary of the glass fragment dispersion area of the first vehicle:

where S is the total distance between the far limits of the scattering areas of glass fragments of oncoming vehicles;

V1, V2 - the speed of the vehicle at the time of the collision.

Figure 1. Determining the location of the collision by the distance of dispersion of glass fragments

When marking the far boundaries of the areas of dispersion of glass fragments, the possibility of error should be excluded, i.e. consider as discarded those fragments that are carried out by the vehicle during its movement after the collision.
According to the width of the road, the place of collision can be indicated approximately in cases where the scattering area has a small width and it is possible to set the direction of the longitudinal axis of the scattering ellipse. It should be borne in mind the possible error in cases where theThe impact of debris to the right and left of the direction of movement of the vehicle was not the same (for example, due to the ricochet of debris from the surface of the second vehicle).

Determination of the place of collision by the final location of vehicles

The direction of movement and the distance that vehicles move from the place of collision depend on many circumstances - the speed and direction of movement of the vehicle, their masses, the nature of the interaction of the contacting parts, resistance to movement, etc. Therefore, the analytical dependence of the coordinates of the vehicle collision site on the quantities that determine these circumstances is very complex. Substitution in the calculation of the formula of quantities, even with small errors, can lead the expert to incorrect conclusions. It is practically impossible to determine the values of these quantities with the required accuracy. It follows that, based on the location of the vehicle after the accident, the location of the collision can only be indicated in some cases.

Figure 2. Determination of the collision site by the final location of the vehicle.

1 - vehicle at the moment of collision; 2 - vehicle after impact

When carrying out expert examinations in cases of violations, the question is often raised as to which side of the carriageway a collision occurred between vehicles moving in parallel directions. To resolve this issue, it is necessary to accurately determine the lateral displacement of the vehicle from the collision site, which, in the absence of data on traces on the road, can be determined by the location of the vehicle after the accident.

The place of collision is most accurately determined in those cases when, after the impact, the vehicles continue to contact (or diverge by a small distance). The transverse displacement of the vehicle from the place of collision then occurs due to their rotation around the center of gravity. The magnitude of the movement of the vehicle is approximately inversely proportional to the values of the mass (or gravity), then to determine the lateral displacement from the collision site, you can use the following formula:

where,

Yk - distance between the centers of gravity of the vehicle after the incident (final), measured in the transverse direction, m;

Yo- distance between the centers of gravity of the vehicle at the time of the incident, measured in the transverse direction, m;

G1 andG2 - vehicle mass, kg.

Clarification of the place of collision by deformations of vehicles

The study of damage received by the vehicle in a collision often allows you to determine the relative position at the time of the collision and the direction of impact. So, if the direction of movement and the location of one of the vehicles that collided at the moment of impact are determined, then the location of the second vehicle and the point at which their initial contact occurred are determined from the damage. In many cases, this makes it possible to determine on which side of the road the collision occurred.

If only the location of the vehicle after the accident is known, then the direction of impact and the probable displacement of the vehicle after the collision can be determined from the damage. The most accurate place of collision can be determined when the distances by which the vehicle has shifted after the impact are insignificant.

In collisions resulting from a sudden turn to the left of one of the vehicles, it is possible to determine the extreme right position of this vehicle at the moment of impact, based on the ability to perform a maneuver under certain friction conditions. In some cases, this makes it possible to find out on which side the collision occurred, if the deformation determines at what angle the impact was made.

Characteristics of vehicle damage

In the event of a collision of vehicles, the main task of the expert study is to determine the mechanism of the collision, as well as to determine the location of the collision site of the vehicle relative to the boundaries of the carriageway and the axial. When installing the collision mechanism, damages on cars are studied (during the transport and trassological examinations), and the main ones when establishing the place of the collision are the traces recorded in the accident diagram. All traces subject to expert analysis can be conditionally divided into two groups - these are traces in the form of damage on vehicles, and traces left by the vehicle on other objects (roadway, on road elements, etc.).

All traces in traceology are classified as:

Volumetric, having three dimensions (length, depth, width);

Surface, two-dimensional;

visible to the naked eye;

Invisible;

Local:

Peripheral, located beyond the zone of influence and formed by residual deformation;

Point and line.

positive and negative;

Layering and delamination.

In transport traceology, traces of a vehicle collision, the classification of which was given earlier, have 9 names adopted to describe damage during transport and trace examinations:

1. Dent - these are damages of various shapes and sizes, characterized by depression of the trace-receiving surface and appear due to its residual deformation;

2. Barbs - these are slip marks with raised pieces, parts of the trace-receiving surface are formed when the solid surface of the particles of one vehicle comes into contact with the less rigid surface of another vehicle.

3. Breakdown - through damage larger than 10 mm (used both in the study of tires and to describe damage to parts of the vehicle).

4. Puncture - through damage up to 10 mm (used only when examining tires.

5. Scratch - shallow, superficial damage, the length of which is greater than the width and without removing the surface layer of the material (despite the paintwork).

6. Layering - associated with the process of trace formation and the transfer of material from one object to another.

7. Detachment - separation of particles, pieces of metal, other substances from the surface of an object.

8. Scraping - the absence of pieces of the upper layer of the trace-perceiving material, caused by the action of the sharp cutting edge of another object.

9. Pressing - pressing the victim by a vehicle to another object or between parts of the vehicle itself (used in the production of complex autotechnical and forensic medical examinations).

The most informative signs indicating the location of the collision site are the traces of the movement of vehicles before the collision. Such marks may be marks of braking, rolling, side shifting, slipping, etc. At the same time, the establishment of the place of collision by traces of the movement of cars requires research both in the nature of their location and belonging to a particular car and even a wheel. So, if the diagram, on the roadway, shows a braking track, which at first was directed straight, and then sharply deviated to the side, then the place of the deviation of the tracks indicates that during the movement of the car it was affected by a shock load, which led to the deviation vehicle movement. The occurrence of a shock load is a fact of the interaction of cars in a collision. Therefore, when determining the place of collision, both the place of change in the direction of braking marks and the location of the place of primary contact in the car itself, which is established when determining the mechanism of the collision, are taken into account.

Lateral shear marks also indicate that their formation was caused by a collision of vehicles, and when certain tracks are identified as belonging to specific wheels of the collision mechanism, the collision site is determined.

The trace information indicating the location of the collision site includes traces in the form of a scree of earth or dirt from the lower parts of the vehicle during a collision, as well as traces in the form of scratches, burrs, potholes on the road left by deformed parts of the vehicle after a collision. In this case, when establishing the place of collision, it is first necessary to establish which part and by which car these marks were left on the road. This is established during an expert review of damaged cars. This also takes into account the collision mechanism, that is, the possibility of moving a car that left a mark on the road from the immediate place of the collision. Most often, in the accident scheme, there is only a scree of glass fragments of small parts from cars, which, moreover, occupies both lanes. In accordance with guidelines, a scree of glass fragments and other small parts of cars that separated during their collision indicate only the zone in which the collision site was located, and not the place itself. Therefore, the determination of the coordinates of the collision site by the location of the talus of glass fragments, as well as bulk cargo in this case, can be done by excluding territories. The essence of this method is that the scree zone is first divided into two sections and, taking into account the study of the collision mechanism, the final position of the vehicle, as well as other traces of the movement of the vehicle, they do not independently carry informative signs of the location of the collision site, one of the sections is excluded. Then the remaining area is again divided into two zones, and so on.

When applying this method, it is advisable to use full-scale modeling at the scene of an accident or planar modeling in a scale scheme.

When installing the vehicle collision mechanism, as noted, there is trace information in the form of damage on the vehicles themselves. At the same time, in transport traceology, there is no distinction between objects that are trace-forming and trace-receptive, because any damage area is both trace-forming and trace-receiving at the same time. In expert practice, the establishment of a collision mechanism based on damage to cars consists of the following stages of research: a separate study, a comparative study, and a natural comparison of the vehicle. At the same time, if the first two stages are mandatory, without which the installation of a collision mechanism is impossible, then the third stage cannot always be carried out, and the impossibility of its implementation does not depend on the expert. In this case, the expert must conduct a simulation based on the first two stages of the study. It is necessary to point out another type of trace information examined by experts in the course of carrying out complex autotechnical and forensic examinations. These traces are traces on the clothes of the victim, as well as traces in the form of bodily injuries on the body of the victim. The study of such traces in conjunction with traces on the vehicle makes it possible to establish the mechanism of a car collision with a pedestrian.

The most complex studies should be considered studies to determine the identity of the person who was driving the car at the time of the accident. In this case, traces on the road, traces on the vehicle, as well as traces on the bodies of people who were in the car at the time of the incident are examined.

Analyzing the above, it should be pointed out that the assessment of trace information in each specific case is individual and cannot be a once and for all established method, but requires abstract thinking from the expert, covering the entire gamut of traces, as well as taking into account the described evaluative features in the traces.

Application

Examples of the characteristic relative position of vehicles at the moment of collision (depending on the angle between their speed vectors):
1. Longitudinal, counter, straight, blocking, central, front.