Typical accident vehicle accident before the instantaneous velocity calculation recommended the use of public

Table B.1 (Continued) typical accident vehicle accident before the instantaneous velocity calculation recommended formula table

Serial number

Typical forms of accidents

The vehicle accident before the instantaneous speed recommended calculation method

Auto rolling or jumping into an obstacle

Between -- collision of vehicle centroid position and the rolling or jumping after the first contact with the ground of the centroid position of horizontal distance, in meters (m);

The vertical distance from the car drop -- or ascending, take the "+" drop, rise from the "-", units of meters (m).

Note: this type is the empirical formula, can modify the actual work.

B.2 data collecting method of commonly used foundation

The vehicle speed in a traffic accident technical identification of basic data collection method see B.2.1 ~ B.2.8.

B.2.1 longitudinal sliding friction coefficient, can be on the scene of a traffic accident or similar road test; not available in the experimental condition, can also refer to the B.3 selection, and then use the value correction. Slide friction coefficient can use its and longitudinal slip between adhesion coefficient = 0.97 +0.08, obtained by calculation.

B.2.2 adhesion coefficient correction value, all wheel brake = 1, a front wheel and a rear wheel brake = 0.5, only the front or rear brake value as the automobile form and decide, for the front engine front drive car in good road only front wheel brake = 0.6 ~ 0.7, and only rear wheel braking = 0.2 ~ 0.3.

Sliding distance of B.2.3 vehicle collision for vehicle braking trace length, available tape, laser range finder or close range photography measurement method, the standard unit for metres.

The rolling resistance coefficient B.2.4 vehicles, can be on the scene of a traffic accident or the similar road measured, in does not have the experimental condition, can also refer to the B.3 selection.

Friction coefficient of B.2.5 vehicle and the ground, value can refer to B.3 selection.

B.2.6 road slope, can be used for portable braking performance tester or level in traffic accident scene measurement.

B.2.7 slip angle of deviation to the direction of travel of the vehicle and the collision point on the road projection projection point on the road vehicle centroid and stop when the vehicle line angle, can be calculated using the Pythagorean theorem.

B.2.8 vehicle plastic approximate calculation method of deformation are as follows.

(the schematic diagram of vertical projection deformation of vehicle everywhere on the ground. Type of vehicle: -- the amount of plastic deformation. -- vehicle plastic deformation minimum. -- vehicle plastic deformation maximum. -- vehicle plastic deformation at a minimum distance of maximum. Vehicle side -- was the width of deformation. (unit: m))

B.3 road adhesion coefficient reference value table

Road adhesion coefficient values are shown in table B.3.1 to B.3.5.

Table B.3.1Vehicle longitudinal sliding friction coefficient reference value table

	Stem Dry	The tide Wet
The following 48km/h	More than 48km/h	The following 48km/h	More than 48km/h
Concrete Pavement	The new pavement	0.80 1	0.70 0.85	0.50 0.80	0.40 0.75
Pavement wear small	0.60 0.80	0.60 0.75	0.45 0.70	0.45 0.65
Pavement high abrasion	0.55 0.75	0.50 0.65	0.45 0.65	0.45 0.60
Asphalt Pavement	The new road	0.80 1	0.60 0.70	0.50 0.80	0.45 0.75
Pavement wear small	0.60 0.80	0.55 0.70	0.45 0.70	0.40 0.65

Table B.3.1 (Continued)Vehicle longitudinal sliding friction coefficient reference value table

	Stem Dry	The tide Wet
The following 48km/h	More than 48km/h	The following 48km/h	More than 48km/h
Asphalt Pavement	Pavement high abrasion	0.55 0.75	0.45 0.65	0.45 0.65	0.40 0.60
Tar at	0.50 0.60	0.35 0.60	0.30 0.60	0.25 0.55
The gravel road	0.40 0.70	0.40 0.70	0.45 0.75	0.45 0.75
Ash Pavement	0.50 0.70	0.50 0.70	0.65 0.75	0.65 0.75
Ice road	0.10 0.25	0.07 0.20	0.05 0.10	0.05 0.10
Snow pavement	0.30 0.55	0.35 0.55	0.30 0.60	0.30 0.60

Table B.3.2When the overturned body sliding friction coefficient reference value table

Sliding conditions	The coefficient of friction
The side body truck skidding on the concrete pavement	0.3 0.4
The overturned car sliding on the concrete pavement	0.3
The car overturned slide in crude asphalt pavement	0.4
The car slide on the gravel road	0.5 0.7
Car car sliding in dry grass	0.5
Body outer panel on Asphalt Pavement	0.4
Body outer panel on the dirt road	0.2
Body outer panel of body outer panel	0.6
Overturned motorcycle taxi	0.55 0.7

Table B.3.3 motorcycle longitudinal sliding friction coefficient reference value table

Motorcycle name	Only rear wheel braking	Front and rear wheel brake
Honda SLl25	0.31 0.40	0.53 0.67
Toyota 3.50	0.36 0.43	0.62 0.72
Toyota XBS00R	0.35 0.42	0.65 0.76
BMW R900	0.3L ~ 0.42	0.72 0.87
Harley DavidsonFLH	0.36 0.51	0.63 0.88

Table B.3.4 dress the human body and the ground friction coefficient reference value table

	Male (71kg weight)	Female (44kg weight)
Asphalt pavement	About 0.52	About 0.44
Concrete pavement	About 0.42	About 0.44
Cement concrete pavement	About 0.32	About 0.26
The pavement	About 0.57	About 0.5
Clay road	About 0.52	About 0.48
Dry sandy coast	About 0.44	About 0.5
Moist sandy coast	About 0.52	About 0.56
Macadam pavement	About 0.46	About 0.5
Finishing off the lawn	About 0.35	About 0.36
Not finishing off the lawn	About 0.46	About 0.52

Table B.3.4 (Continued) the coefficient of friction wear the human body and the ground reference value table

	Male (71kg weight)	Female (44kg weight)
The higher the grass	About 0.54	About 0.56
Low grass	About 0.56	About 0.65
Dry farmland	About 0.58	About 0.59

Table B.3.5Auto rolling resistance coefficient reference value table

Pavement condition	Rolling resistance coefficient f
Good smooth asphalt pavement	About 0.01
Good smooth concrete pavement	About 0.011
Good rubble concrete pavement	About 0.014
A good stone pavement	About 0.02
A good flat no pavement	About 0.04
Correction of defective stone pavement	About 0.08
Sand road new	About 0.12
Sand or stone road	About 0.16
Sand or clay road loose	About 0.2 ~ 0.3