Untangling the Chain: How Accident Reconstructionists Determines Who Hit Whom First in Multi-Vehicle Collisions

 

In the aftermath of a multi-vehicle collision, the scene is often chaotic. Crumpled bumpers, scattered debris, and conflicting driver accounts create a confusing picture of what actually happened. For insurance adjusters, attorneys, and law enforcement, a key question often arises: Who hit whom first?

When three or more vehicles are involved, determining the sequence of impacts is critical for assigning liability, understanding injury mechanisms, and resolving claims fairly. That’s where Garrett Forensics’ accident reconstruction experts step in—with the technical expertise to bring clarity to even the most complex crash scenes.

 

Common Three-Vehicle Collision Scenarios
While every incident is unique, certain collision patterns frequently arise in three-vehicle crashes:

Rear-End Chain Reaction
A common highway or intersection scenario: Vehicle A stops or slows, Vehicle B fails to stop in time and hits A, and Vehicle C strikes B from behind. At first glance, this may seem straightforward—but overlapping damage, staggered impacts, or evasive maneuvers can complicate the story.

 

T-Bone Plus Secondary Collision
Vehicle A runs a red light and strikes Vehicle B in the side. The force pushes B into Vehicle C, which was stopped or traveling in a perpendicular direction. Determining whether Vehicle C’s damage was caused by A or B is crucial for claims and liability.

 

Multi-Vehicle Intersection Impact
Vehicles A, B, and C enter an intersection simultaneously from different directions. After multiple points of contact, all vehicles sustain damage—but the origin and sequence of those impacts are far from obvious.

 

How Garrett Forensics Reconstructs the Sequence of Events
At Garrett Forensics, our team of ACTAR-certified accident reconstructionists and engineers uses a disciplined, evidence-based approach to determine the crash sequence. Here’s how we do it:

1. Physical Evidence Collection
Vehicle damage profiles: We assess deformation patterns, crush depth, paint transfers, and bumper height misalignments to determine who struck whom and at what angle.

Scene documentation: Skid marks, yaw marks, debris fields, and fluid trails all tell a story about speed, direction, and point of impact.

EDR data analysis: Many modern vehicles store pre-crash data (speed, brake application, throttle position) in their Event Data Recorders (EDRs). This information is invaluable in confirming timing and driver behavior.

 

2. Damage Timing and Overlap
In chain-reaction crashes, we analyze whether the damage occurred in a single continuous event or in separate, sequential collisions. For example, if Vehicle B shows pre-impact damage before being hit by Vehicle C, it suggests that A hit B first.

 

3. Reconstruction Modeling
Using physics-based calculations, we recreate the crash dynamics. This helps determine the sequence of events and can be presented in legal proceedings or insurance reviews.

 

4. Witness and Driver Statements
We cross-reference driver accounts with the physical and digital evidence. Discrepancies often reveal inaccuracies or misunderstandings that can be resolved through forensic analysis

 

Case Study Snapshot
In a recent case, Garrett Forensics investigated a three-vehicle pile-up on a suburban roadway. All drivers blamed one another, and the insurance companies were locked in dispute. Through EDR analysis, crush pattern assessment, and physical scene measurements, our team determined:

Vehicle A made a sudden stop due to a road hazard.

Vehicle B struck A at low speed, barely damaging A’s bumper.

Vehicle C, distracted and traveling at a higher speed, collided with B, pushing it further into A.

Our findings showed that Vehicle C caused the majority of the damage—and our report became the key piece of evidence in settling the claim.

 

Trusted Clarity in Complex Collisions
When multiple vehicles are involved, identifying the first impact is essential—but far from simple. Garrett Forensics brings clarity through expert analysis, objective data, and courtroom-ready documentation.

 

If you’re handling a multi-vehicle collision case, let Garrett Forensics determine the sequence of events and help you move from confusion to resolution.