_{1}

In order to improve the accuracy of car side collision accident reconstruction, a domestic accident case is taken as an example to reconstruct the accident through PC-CRASH and design the orthogonal experiment. Through experiments, the weight ranking of PC-CRASH side impact reconstruction is obtained. According to the weight of the parameters, the accident case is reconstructed again. The results show that th e error between the reconstructed result and the actual accident result after the targeted adjustment of the parameter is significantly smaller than the error between the reconstruction result obtained from the unadjusted adjustment parameter and the actual accident result. Therefore, it is verified that the accident reconstruction according to the weighting of the affected parameters can improve the accuracy of the result of PC-CRASH accident reconstruction of the side collision of the car.

According to the statistics of the Traffic Management Bureau of the Ministry of Public Security of the People’s Republic of China [

In the current road traffic accident treatment, the reappearance and identification of the accident process is mainly to solve the collision process of cars and pedestrians when the accident occurs, in order to assist the traffic police to search and confirm the scene of the road traffic accident. At present, the software used for car crash analysis is PC-CRASH [

The sensitivity analysis of the velocity direction parameters before the collision and the position parameters of the collision center in the typical collision model is analyzed by Jianping Pei [

In this paper, the weight coefficients of car side impact accidents reconstructed by PC-CRASH are studied. Through the reconstruction of a real accident case, sorting of the input parameters design orthogonal experiment which affect the PC-CRASH accident reconstruction. Then an accident reconstruction method for adjusting the PC-CRASH input parameters according to the weight coefficient is proposed, and the effectiveness of the new method is verified by the two reconstruction of the accident case.

Using PC-CRASH to restore traffic accidents, first of all, we need to collect and organize the PC-CRASH input parameters related to the accident. According to the difference of the method and accuracy of parameter acquisition, the relevant parameters are divided into three categories: accurate parameters, measurement parameters, and empirical parameters (

In the above parameters, the estimation of the speed before collision is usually required by calculation formula. According to the law of conservation of energy and the calculation method of sequence number 3 in ≪ GB/T 33195-2016 road traffic accident speed identification ≫ [

v 1 = ( 2 g s 1 k 1 φ 1 cos α + m 2 m 1 2 g s 2 k 2 φ 2 sin β ) ∗ 3.6 (1)

v 2 = ( m 1 m 2 2 g s 1 k 1 φ 1 sin α + 2 g s 2 k 2 φ 2 cos β ) ∗ 3.6 (2)

In the formula:

v 1 v 2 ―The speed of two collision cars at the moment of a traffic accident (km/h)

g―Gravitational acceleration, take 9.8 m/s^{2}

φ 1 φ 2 ―Sliding adhesion coefficient of two collision cars

k k 2 ―Correction value of the adhesion coefficient of two collision cars

s 1 s 2 ―Slip distance after collision of two collision cars (m)

α β ―Slip deflection angle of two collision cars (˚)

m 1 m 2 ―The quality of two collision cars (kg)

3.6―Coefficient of unit conversion

Since the accurate weighing m 1 m 2 can be carried out after the accident, the fixed value of the gravity acceleration g and the correction value of the adhesion coefficient k 1 k 2 are taken, so the above parameters are not taken into consideration when analyzing the influence of the parameters on the side collision accident reconstruction of the PC-CRASH. Because the final position of the two cars is fixed after the collision, the slip distance and slip angle of the two cars depend on the position of the collision point and the selection of the two cars angle when the collision is collided, so it is not considered.

Based on the above analysis, the following 11 parameters that have great impact on accident reconstruction are finally determined.: the position of the collision point, the angle of the two cars in the collision, the speed of the two cars in the collision, the friction coefficient of the tire and the ground, the height of the center of gravity of the two cars, the braking force of the two cars and the angle of the steering wheel of the two cars.

Classification | Parameter type | Software input parameters |
---|---|---|

Accurate parameters | car size parameters | The length, width, height, front suspension, wheelbase and wheelbase of a car. |

Tire parameters | Tire model | |

Safety device | ABS configuration | |

Engine parameters | Engine displacement, power | |

Measurement parameters | car shape parameters | a b c d e f g 1 2 3 4 5 6 7 8 (Specific meaning refer to PC-CRASH software) |

Quality parameters | Total quality of accident participants in collision | |

Position parameter | The relative position and location of the collision point between the participants in the collision. | |

Displacement parameters | The distance from the collision point to the final position. | |

Empirical parameters | Velocity parameter | The speed of each participant in a collision |

Friction coefficient parameters of pavement | The friction coefficient of the tire and the ground | |

Center of gravity parameter | The center of gravity of each participant | |

Operating parameters | The brake response time, braking force, steering wheel direction and size of each participant. |

At 13:00 on January 19, 2016, the driver of the A car was driving from east to west and went to the intersection of the incident and collided with the B car driving from south to north. The accident resulted in damage to the right side of the front of the A car and the body of the B car, and two passengers were injured.

By combining the field trace, the law of conservation of energy, the traditional experience formula, PC-CRASH simulation and so on, after the accident reconstruction is carried out, the specific value of the parameters which have great influence on the reconstruction of the accident is found out in

The final position map of the two cars and the final position of the actual two cars simulated by PC-CRASH are shown in

The weighting sorting of the 11 parameters that have a great influence on the reconstruction of the side collision accidents of the car is required for experimental analysis. However, due to the many factors affecting the test, if each level of each factor is matched with each other for a comprehensive test, the number of trials required will be very large. Therefore, this paper uses the orthogonal test [

There are 11 factors to be considered in this test design, which are represented by A~K. According to the specific values of each parameter obtained by the

Collision point coordinates | Two cars’ collision angle (˚) | A car’s speed (km/h) | B car’s speed (km/h) | Tire and ground friction coefficient | A car’s center of gravity (m) |
---|---|---|---|---|---|

(1938.02, 488.77) | 90 | 60 | 45 | 0.75 | 0.5 |

B car’s center of gravity (m) | A car’s deceleration (m/s^{2}) | B car’s deceleration (m/s^{2}) | A car’s steering wheel corner (˚) | B car’s steering wheel corner (˚) | |

0.5 | 4.0 | 5.4 | −150 | 100 |

above accident reconstruction, an orthogonal test of 11 factors and 3 levels is arranged, in which the values of each level are within a reasonable range of variation, and the factor level table is shown in

According to the factor level table, the distance(X_{1},X_{2})/(m) between the center of gravity of the A and B two cars after the change of parameters and the center of gravity after the actual A and B two cars stopped as the test index. The designed test plan and simulation results are shown in

The direct analysis method of orthogonal test design is to calculate the influence of all factors and levels on the result of the test results through the analysis

Level | Collision point coordinates | Two cars’ collision angle/(˚) | A car’s speed/(km/h) | B car’s speed/(km/h) | Tire and ground friction coefficient | A car’s center height/m |
---|---|---|---|---|---|---|

Symbol | A | B | C | D | E | F |

1 | (1938.02, 488.47) | 80 | 55 | 40 | 0.70 | 0.45 |

2 | (1938.02, 488.77) | 90 | 60 | 45 | 0.75 | 0.50 |

3 | (1938.32, 488.77) | 100 | 65 | 50 | 0.80 | 0.55 |

Level | B car’s center height/(m) | A car’s deceleration/(m/s^{2}) | B car’s deceleration/(m/s^{2}) | A car’ steering wheel corner/(˚) | B car’s steering wheel corner/(˚) | |

Symbol | G | H | I | J | K | |

1 | 0.45 | 3.0 | 4.4 | −140 | 90 | |

2 | 0.5 | 4.0 | 5.4 | −150 | 100 | |

3 | 0.55 | 5.0 | 6.4 | −160 | 110 |

Test | A | B | C | D | E | F | G | H | I | J | K | X1 | X2 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|

1 | (1938.02, 488.47) | 80 | 55 | 40 | 0.70 | 0.45 | 0.45 | 3.0 | 4.4 | −140 | 90 | 7.3 | 16.8 |

2 | (1938.02, 488.47) | 80 | 55 | 40 | 0.75 | 0.50 | 0.5 | 4.0 | 5.4 | −150 | 100 | 7.6 | 2.8 |

3 | (1938.02, 488.47) | 80 | 55 | 40 | 0.80 | 0.55 | 0.55 | 5.0 | 6.4 | −160 | 110 | 6.9 | 4.7 |

4 | (1938.02, 488.47) | 90 | 60 | 45 | 0.70 | 0.45 | 0.45 | 4.0 | 5.4 | −150 | 110 | 9.0 | 0.7 |

5 | (1938.02, 488.47) | 90 | 60 | 45 | 0.75 | 0.50 | 0.50 | 5.0 | 6.4 | −160 | 90 | 8.4 | 2.1 |

6 | (1938.02, 488.47) | 90 | 60 | 45 | 0.80 | 0.55 | 0.55 | 3.0 | 4.4 | −140 | 100 | 11.1 | 2.8 |

7 | (1938.02, 488.47) | 100 | 65 | 50 | 0.70 | 0.45 | 0.45 | 5.0 | 6.4 | −160 | 100 | 10 | 1.7 |

8 | (1938.02, 488.47) | 100 | 65 | 50 | 0.75 | 0.50 | 0.50 | 3.0 | 4.4 | −140 | 110 | 12.9 | 4.6 |

9 | (1938.02, 488.47) | 100 | 65 | 50 | 0.80 | 0.55 | 0.55 | 4.0 | 5.4 | −150 | 90 | 12.2 | 4.2 |

10 | (1938.02, 488.77) | 80 | 60 | 50 | 0.70 | 0.50 | 0.55 | 3.0 | 5.4 | −160 | 90 | 10.5 | 5.3 |

11 | (1938.02, 488.77) | 80 | 60 | 50 | 0.75 | 0.55 | 0.45 | 4.0 | 6.4 | −140 | 100 | 9.3 | 2.1 |

12 | (1938.02, 488.77) | 80 | 60 | 50 | 0.80 | 0.45 | 0.50 | 5.0 | 4.4 | −150 | 110 | 10.6 | 5.8 |

13 | (1938.02, 488.77) | 90 | 65 | 40 | 0.70 | 0.50 | 0.55 | 4.0 | 6.4 | −140 | 110 | 5.9 | 3.1 |

14 | (1938.02, 488.77) | 90 | 65 | 40 | 0.75 | 0.55 | 0.45 | 5.0 | 4.4 | −150 | 90 | 7.1 | 2.9 |

15 | (1938.02, 488.77) | 90 | 65 | 40 | 0.80 | 0.45 | 0.50 | 3.0 | 5.4 | −160 | 100 | 6.0 | 2.5 |

16 | (1938.02, 488.77) | 100 | 55 | 45 | 0.70 | 0.50 | 0.55 | 5.0 | 4.4 | −150 | 100 | 10 | 2.8 |

17 | (1938.02, 488.77) | 100 | 55 | 45 | 0.75 | 0.55 | 0.45 | 3.0 | 5.4 | −160 | 110 | 8.1 | 3.9 |

18 | (1938.02, 488.77) | 100 | 55 | 45 | 0.80 | 0.45 | 0.50 | 4.0 | 6.4 | −140 | 90 | 7.4 | 4.9 |

19 | (1938.32, 488.77) | 80 | 65 | 45 | 0.70 | 0.55 | 0.50 | 3.0 | 6.4 | −150 | 90 | 9.4 | 1.3 |

20 | (1938.32, 488.77) | 80 | 65 | 45 | 0.75 | 0.45 | 0.55 | 4.0 | 4.4 | −160 | 100 | 11.1 | 6.1 |

21 | (1938.32, 488.77) | 80 | 65 | 45 | 0.80 | 0.50 | 0.45 | 5.0 | 5.4 | −140 | 110 | 7.7 | 1.7 |

22 | (1938.32, 488.77) | 90 | 55 | 50 | 0.70 | 0.55 | 0.50 | 4.0 | 4.4 | −160 | 110 | 11.5 | 5.2 |

23 | (1938.32, 488.77) | 90 | 55 | 50 | 0.75 | 0.45 | 0.55 | 5.0 | 5.4 | −140 | 90 | 12.4 | 5.7 |

24 | (1938.32, 488.77) | 90 | 55 | 50 | 0.80 | 0.50 | 0.45 | 3.0 | 6.4 | −150 | 100 | 10.4 | 4.7 |

25 | (1938.32, 488.77) | 100 | 60 | 40 | 0.70 | 0.55 | 0.50 | 5.0 | 5.4 | −140 | 100 | 6.6 | 2.7 |

26 | (1938.32, 488.77) | 100 | 60 | 40 | 0.75 | 0.45 | 0.55 | 3.0 | 6.4 | −150 | 110 | 6.2 | 3.5 |

27 | (1938.32, 488.77) | 100 | 60 | 40 | 0.80 | 0.50 | 0.45 | 4.0 | 4.4 | −160 | 90 | 7.5 | 1.8 |

of extreme difference and comprehensive comparison in order to determine the optimal test scheme, sometimes also called the extreme analysis method. The range is large shows that this factor has a great influence on the index and is an important factor; the range is small shows that this factor has little influence on the index, and is usually an unimportant factor, and the extreme calculation formula for each factor is the difference. The range formula for each factor is

R j = max 1 ≤ l ≤ r K ¯ l j − min 1 ≤ l ≤ r K ¯ l j , j = 1 , 2 , ⋯ , p (3)

In the formula:

K ¯ l j = K l j / m ( l = 1 , 2 , ⋯ , r ; j = 1 , 2 , ⋯ , p )

K l j ( l = 1 , 2 , ⋯ , r ; j = 1 , 2 , ⋯ , p ) represent the sum of the m test results corresponding to the horizontal l in the column j of the orthogonal table, and m is the number of times that each level appears in the test plan.

Through the above range analysis table, comparing the range values of various factors, it can be concluded that when PC-CRASH is used to reconstruct the side impact accident:

1) Parameter weight ranking of A car accident reconstruction is：Speed of side damaged collision car > Deceleration of side damaged collision cars > Collision point coordinates > Center height of side damaged collision cars > Tire and ground friction coefficient = Steering wheel corner of side damaged collision cars > Speed of frontal damaged collision car = Steering wheel corner of frontal damaged collision cars > Two cars’ collision angle = Center height of frontal damaged collision cars = Deceleration of frontal damaged collision cars.

2) Parameter weight ranking of B car accident reconstruction is: Speed of frontal damaged collision car > Deceleration of side damaged collision cars > Center height of frontal damaged collision cars > Two cars’ collision angle = Steering wheel corner of side damaged collision cars > Deceleration of frontal damaged collision cars = Steering wheel corner of frontal damaged collision cars>Speed of side damaged collision car > Collision point coordinates > Center height of side damaged collision cars = Tire and ground friction coefficient.

First, the classical car speed formula (1) (2) and the calculation of the accident parameters required by the car speed are shown in

The parameters in

By selecting the speed in the speed range of the two cars and the weight sorting of the reconstruction parameters of the car side impact PC-CRASH accident reconstruction, the accident case was reconstructed second times and the second reconstruction results were shown in

Test | A | B | C | D | E | F | G | H | I | J | K |
---|---|---|---|---|---|---|---|---|---|---|---|

9.5 | 8.9 | 9.1 | 6.8 | 8.9 | 8.9 | 8.5 | 9.1 | 9.9 | 8.9 | 9.1 | |

8.3 | 9.1 | 8.8 | 9.1 | 9.2 | 8.9 | 8.9 | 9.1 | 8.9 | 9.2 | 9.1 | |

9.2 | 8.9 | 9.1 | 11.1 | 8.9 | 9.1 | 9.6 | 8.8 | 8.2 | 8.9 | 8.8 | |

1.2 | 0.2 | 0.3 | 4.3 | 0.4 | 0.2 | 1.1 | 0.2 | 1.7 | 0.3 | 0.4 |

Test | A | B | C | D | E | F | G | H | I | J | K |
---|---|---|---|---|---|---|---|---|---|---|---|

4.5 | 5.2 | 5.7 | 4.5 | 4.4 | 5.3 | 4.0 | 5.0 | 5.4 | 4.9 | 5 | |

3.7 | 3.3 | 2.9 | 2.9 | 3.7 | 3.2 | 3.5 | 3.4 | 3.3 | 3.2 | 3.1 | |

3.6 | 3.3 | 3.1 | 4.4 | 3.7 | 3.3 | 4.2 | 3.3 | 3.1 | 3.7 | 3.7 | |

0.9 | 1.9 | 2.7 | 1.6 | 0.7 | 2.1 | 0.7 | 1.7 | 2.3 | 1.7 | 1.9 |

Speed calculation parameters of two cars | Range of value | Speed calculation parameters of two cars | Range of value |
---|---|---|---|

φ_{1} | 0.75 ± 0.05 | φ_{2} | 0.75 ± 0.05 |

s_{1}/m | 17.5 | s_{2}/m | 9.5 |

m_{1} | 1670 | m_{2} | 1540 |

α/(˚) | 40 | β/(˚) | 41 |

Taking the error value of the position of the car’s gravity center after the two reconstruction and the center of gravity of the actual car after stopping, the two accident reconstruction results were evaluated. The results of the two accident reconstruction results in

As can be seen from

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

Center of gravity position error of A car/m | Center of gravity position error of B car/m | |
---|---|---|

First reconstruction | 0.22 | 0.27 |

Second reconstruction | 0.15 | 0.19 |

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

(1945.42, 472.94)

(1950.31, 475.40)

1) Through the orthogonal experiment and the range analysis of the selected 11 parameters, it can be seen that the biggest influence factor on the car side collision accident reconstruction is the speed of the two cars before the collision.

2) According to the obtained PC-CRASH accident reconstruction parameter weight and the targeted adjustment parameters can improve the accuracy of accident reconstruction.

The authors declare no conflicts of interest regarding the publication of this paper.

Li, C. (2018) Parameter Weight Analysis of Car Side Impact Accident Reconstruction. Open Access Library Journal, 5: e4756. https://doi.org/10.4236/oalib.1104756