Case of the Month: A Freeway Collision

Oct 1, 2016 by

A three-vehicle chain reaction collision occurred on the Santa Ana Freeway. The first vehicle in the chain was a white 2007 Honda Pilot. The middle vehicle was a blue 2015 Honda Civic. The last vehicle in the chain was a brown 2016 Ford C-Max. At dispute: Did the Ford made contact with the rear of the Honda Civic, and if so, what was the sequence of collisions in the chain reaction event?

Our expert’s conclusions in this matter were based upon a review of the photographs of all three vehicles, repair estimates, and the South Los Angeles CHP Traffic Collision Report.

 


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The rear of the lead Honda had minor cosmetic damage to its rear bumper cover and a fracture to the left rear red reflector.

The front of the middle-position Honda Civic had damage to its front bumper requiring replacement of the front bumper cover, both front bumper stiffeners, and the energy absorber. The grille was broken, and both radiator supports require replacement. The leading edge of the hood was slightly dented and required replacement.

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There was damage to the rear of the Civic that could not be attributed to contact from the front of the Ford. The damage estimate called for repair of the rear body panel and pulling of the left frame, with repair of the left rail frame end. The rear bumper cover required replacement, as well as both side supports and the rear bumper energy absorber.

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There was no visible or reported damage to the brown Ford. The CHP report listed all the damage to the three vehicles as minor. The CHP report also showed a depiction of damage to the front of the Ford, however there was no damage evident to the front of the Ford.

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The following chart lists the significant relevant characteristics of the three vehicles.

VEHICLE CURB WEIGHT BUMPER HEIGHT
2007 Honda Pilot 4,310 pounds Rear bumper 27 inches
2015 Honda Civic 2,740 pounds Front bumper 20 inches
Rear bumper 24 inches
2016 Ford C-Max 3,607 pounds Front bumper 20 inches

When two vehicles collide the difference in their speed and direction results in the total kinetic energy of their collision system. This kinetic energy is partitioned between the two vehicles inversely proportional to their weights with the lighter vehicle receiving the greater portion of the energy. The energy is dissipated through the bending of metal, and the fracturing of rigid parts, plus heat and noise.

The damage to the vehicles is the signature of the expended kinetic energy.  It also reflects the energy partition with the lighter vehicle showing more damage than the heavier vehicle. Based on the difference in the damage to the front of the blue Honda Civic and the rear of the white Honda Pilot and considering the difference in the weights of the two vehicles, the damage to these vehicles was commensurate. Conversely, based on the lack of damage to the front of the brown Ford and the significant damage to the rear of the blue Honda Civic, it was evident that the damage to the rear of the Honda Civic was not produced by contact from the front of the Ford.

The CHP report summarized a statement from the Ford driver where she allegedly said she collided with the rear of the Honda Civic. However in a statement to her insurance company she said she believed she did not make contact with the rear of the Honda Civic. Additionally, the driver of the lead Honda Pilot stated to his insurance carrier that he only felt and heard one collision. He said he did not believe there was contact between the Ford and the rear of the Honda Civic. That statement substantiated the Ford driver’s version of the collision wherein she claimed that she did not collide with the rear of the Honda Civic. Certainly it would not be possible for the Ford to produce all the visible damage to both the blue Honda Civic and the white Honda Pilot and receive no damage as a result of that impact.

Accordingly, our expert strongly disagreed with the conclusions of the CHP Traffic Collision Report.  The CHP report placed the Ford driver at fault for this collision sequence and attributed all of the damage in the collisions to a rear-end impact between the front of the brown Ford and the rear of the blue Honda Civic. There was no evidence to support such a conclusion, and, in fact, the evidence strongly refuted such a statement.

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