In most car accident cases, the liability analysis is straightforward. A rear-end collision. A red light violation documented in the police report. A left turn into oncoming traffic. The police report, the witness statements, and the vehicle damage patterns tell the story. But some accidents involve disputed facts that the available evidence does not resolve on its own. In those cases, accident reconstruction may be the only way to establish who was at fault. This is done through expert analysis of the physical evidence to determine how the collision occurred. Reconstruction is not needed in every case. When it is needed, it is often the difference between a recovery and no recovery.
The decision to retain an accident reconstruction expert is a significant one. These experts charge substantial fees — typically $15,000 to $50,000 in a serious case, depending on the scope of the analysis and whether they testify at trial. The investment makes sense when liability is disputed, when the potential recovery is large enough to justify the cost, and when the physical evidence supports a reconstruction opinion. Investing in this type of expert opinion can change the outcome of a case.
What accident reconstruction involves
An accident reconstruction expert analyzes the physical evidence of the collision and applies principles of physics and engineering to reconstruct the speed, direction, and movement of each vehicle before, during, and after impact. The expert examines vehicle damage patterns and crush depth, the point of impact, tire marks and roadway scuffs, debris scatter, roadway geometry and grade, traffic signal timing, sight lines and visibility conditions, weather and road surface conditions at the time of the collision, and in modern vehicles, electronic data from event data recorders and vehicle control systems.
Reconstruction experts typically hold engineering degrees — mechanical, civil, or biomechanical — and have specialized training in accident reconstruction through organizations such as the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) or the Society of Automotive Engineers. Their analysis is documented in a formal report with calculations, diagrams, and in some cases computer simulations or 3D scene models.
When reconstruction is necessary
Reconstruction is most commonly needed in intersection collisions where both drivers claim they had the green light, and neither witness statements nor traffic camera footage resolves the dispute. Intersection signal timing data from the municipality, combined with vehicle approach speeds calculated from damage and skid marks, can establish which driver entered the intersection on green.
High-speed collisions where the at-fault driver denies speeding often require reconstruction. The crush depth of the vehicles, the post-impact trajectories, and the distance from point of impact to point of rest all reveal the approach speeds. A driver who claims to have been traveling at the speed limit can be shown, through reconstruction, to have been traveling significantly faster.
Head-on collisions where one driver claims the other crossed the center line can be reconstructed from the damage patterns and the final resting positions of the vehicles. Multi-vehicle chain reactions where the sequence of impacts is disputed require reconstruction to establish which collision happened first and which driver initiated the chain. Collisions involving commercial vehicles where the driver or company claims a mechanical failure caused the accident often involve reconstruction to evaluate whether the mechanical condition, the driver’s actions, or both caused the crash.
Accidents involving pedestrians, motorcyclists, or bicyclists often require reconstruction because the dynamics differ significantly from vehicle-to-vehicle collisions. The distance from the point of impact to the point of rest, the injury patterns, and the damage to the vehicle can establish the vehicle’s approach speed and the pedestrian’s position. In disputed cases where the driver claims the pedestrian stepped into the roadway unexpectedly, reconstruction can evaluate whether the driver had adequate time and distance to react.
The event data recorder
Most passenger vehicles manufactured since 2014 contain an event data recorder — commonly called a black box — that records data from the seconds before and during a crash. The EDR captures vehicle speed, brake application, throttle position, steering input, seatbelt use, and airbag deployment data. This data can be downloaded by a trained technician using specialized equipment. Once downloaded, it often resolves disputes about speed, braking, and driver inputs with far more certainty than witness testimony.
Commercial vehicles have electronic logging devices and sometimes more sophisticated recording systems that capture GPS data, speed data, hours-of-service records, and in some cases dashboard camera footage. The data must be preserved promptly because the recording devices overwrite older data on a rolling basis. A preservation demand sent within days of the accident can capture data that would otherwise be lost within weeks. The EDR data is often the single most valuable piece of evidence in a disputed liability case — it answers questions about speed and braking that witnesses can only estimate.
Physical evidence must be preserved for reconstruction to work
The reconstruction expert needs the physical evidence to analyze. Without evidence, even the best expert cannot reconstruct the accident. This is why early evidence preservation is critical in any case where liability is disputed. Vehicle damage must be documented through detailed photographs from multiple angles before repairs begin. If the vehicle is being totaled and scrapped, the expert should inspect it at the tow yard before it is removed. The damage patterns, crush depth, and direction of force are information that cannot be reconstructed after the vehicle is gone.
Tire marks, debris scatter, fluid spills, and roadway conditions at the scene must be photographed and measured quickly. Rain, traffic, or routine road maintenance can erase scene evidence within hours. Police accident reports sometimes include basic scene measurements, but independent scene documentation is often needed for expert analysis.
Event data recorder information — the “black box” data in modern vehicles — must be downloaded before the vehicle is repaired, scrapped, or the data is overwritten. Many vehicles retain EDR data for a limited number of ignition cycles or hours of operation. If the vehicle is driven or powered on after the accident, the pre-crash data may be overwritten. Commercial vehicles with telematics systems store data on company servers and require preservation letters directed to the carrier, not just the vehicle itself.
Surveillance footage from businesses near the intersection, traffic cameras operated by NYC DOT or the NYS Department of Transportation, and dashcam footage from nearby vehicles can all provide critical evidence. This footage can be overwritten in as little as a week's time. Evidence preservation letters sent within the first week can prevent the destruction of this footage.
Reconstruction and comparative negligence
New York’s pure comparative negligence standard under CPLR 1411 means that the allocation of fault directly affects the settlement value. A plaintiff who is 30% at fault recovers 70% of their damages. Every percentage point matters. Reconstruction analysis can shift the fault allocation in ways that witness testimony alone cannot. When the defense argues that the plaintiff contributed to the collision by speeding, by failing to yield, or by inattention, reconstruction evidence can refute those arguments with scientific analysis rather than competing testimony.
How reconstruction affects settlement value
A favorable reconstruction report fundamentally changes the carrier’s evaluation of a case. What was a he-said-she-said liability dispute becomes a case with scientific evidence supporting the plaintiff’s version. The carrier’s reserve increases. The settlement authority increases. Cases that may have settled for a discount because of disputed liability settle at full value because liability is no longer in genuine dispute. The cost of the reconstruction expert is worth every penny when it achieves the outcome it is intended. In cases where the damages exceed seven figures, the cost of reconstruction is a small fraction of the incremental recovery the expert’s analysis produces.
The defense also retains reconstruction experts in serious cases. The battle between opposing reconstruction experts at trial is one of the most important aspects of a disputed liability case. The jury ultimately decides which expert’s analysis is more credible. An expert with strong credentials, clear methodology, and careful documentation of the underlying evidence is more persuasive than one who appears to have reverse-engineered an opinion to support the client’s position. Selecting the right expert and preserving the evidence they need is how the reconstruction battle is won.
How Schwartzapfel Holbrook uses accident reconstruction
At Schwartzapfel Holbrook, we retain accident reconstruction experts when the liability analysis requires it. We preserve the evidence the expert needs from the first week of the case: detailed vehicle photographs, scene documentation, event data recorder downloads, and any available surveillance or traffic camera footage. In disputed liability cases, reconstruction analysis can be the difference between a defensible claim and one the carrier dismisses as a credibility contest between two drivers. We invest in the reconstruction evidence that supports the liability case with the same thoroughness we apply to the medical evidence that supports the damages case, because both are necessary for the outcome the client deserves.
Schwartzapfel Holbrook / Fighting For You