Solving

The known conditions

Formula

The average speed of vehicles in a given period of time at a long distance

Time

: distance

(unit: m/s)

The locked state wheel speed

: vehicle longitudinal sliding friction coefficient

Modified value: vehicle attachment coefficient

(unit: m/s²)

According to the vehicle collision point to the stop point distance, according to the law of conservation of energy, computation of the collision instant vehicle speed

: vehicle braking deceleration

: distance

(unit: m/s)

According to the terminal velocity of a known speed for vehicles in the accelerated after the

: known speed

The acceleration of the vehicle

(unit: m/s)

The critical velocity in horizontal road when turning the vehicle

: turning radius

Slide: adhesion coefficient

(unit: m/s)

Critical speed of turning in a sloping road to vehicle turning on the vehicle

: turning radius

Slide: adhesion coefficient

: Road tilt

(unit: m/s)

The critical velocity in horizontal road side turn over vehicle

: turning radius

: track

The vehicle height

(unit: m/s)

Effective collision velocity

1: the quality of vehicle

2: the quality of vehicle

1: vehicle collision speed in the instant before

2: vehicle collision speed in the instant before

(unit: m/s)

(unit: m/s)

The car frontal impact effective collision velocity

: car shape variables

The car rear end collision effective collision velocity

: car shape variables

Law of conservation of momentum equation

: 1, 2, the quality of the vehicle

: 1, 2, the vehicle speed before collision moment

: 1, 2, the vehicle collision instantaneous speed

(the formula for the vector relation)

A vehicle braking speed brake marks obvious before collision

: vehicles in collision velocity

Braking coordination time

: the road slope (positive negative uphill, downhill)

: longitudinal sliding friction coefficient

: vehicle braking deceleration

Before the collision: vehicle slip distance

(unit: m/s)