Omega Accident Reconstruction Services

Crash Phases and Chain of Events in a Motor Vehicle Crash

There are three phases in all motor vehicle crashes.  First is the Pre-Crash, second is the Impact and third is the Post-Impact. 

In the Pre-Crash, the following chain of events takes place. 

1.  Encroachment - This is when the vehicles begin to approach each other, or, in the case of a one vehicle crash, when the vehicle begins to approach the object it is about to strike.

2.  First Possible Perception - This is the point before the crash where it is possible for the driver of the vehicle to realize that a crash is eminent and there is likely still time to take evasive action.

3.  Point of Actual Perception -   This is the actual point where the driver realizes a crash is eminent and the driver is now deciding to take evasive action. 

4.  Start of Evasive Action - This is where the driver begins to take evasive action to try and avoid a crash.  This can be indicated by tire marks on the roadway such as skids or yaw marks.

5.  Point of No Escape -  This is the event where it is too late for evasive action. No matter what the driver does, a crash cannot be avoided.   

In the Impact Phase, the chain of events continue.

6.  First Harmful Event - This is where the first initial contact of the vehicles takes place. 

7.  Maximum Engagement -  This is the furthest penitration of one vehicle into another vehicle or object.  This is where the greatest contact area or depth of the crush has been acheived.

8.  Disengagement -  This is the point in the crash where the vehicles begin to come apart.  All of the energy in both vehicles has been depleted and are no longer crushing into each other.

The final Chain of Event occurs in the Post-Crash Phase.

9.  Final Rest - This is the point where all vehicles come to a complete stop. 

It takes an experienced accident reconstructionist to determine where each of the Chain of Events took place in a crash.  Locating each event on the roadway plays a crucial role in determining neglegence in a crash.  Questions such as "COULD the driver(s) have done something to avoid the crash",  " Was it POSSIBLE for the drivers to avoid the crash" and DID the driver take evasive action at all" need to be answered, especially in a case where serious injury or a fatality is involved.