---
title: "Accident Reconstruction Expert Witness’ Supplemental Report Correcting Mathematical Errors Admitted"
meta:
  "og:description": "The supplemental report of the accident reconstruction expert witness, which corrected certain calculations, was timely and did not introduce new opinions"
  "og:title": "Accident Reconstruction Expert Witness’ Supplemental Report Correcting Mathematical Errors Admitted"
  author: "Expert Witness Profiler"
  description: "The supplemental report of the accident reconstruction expert witness, which corrected certain calculations, was timely and did not introduce new opinions"
---

# Accident Reconstruction Expert Witness’ Supplemental Report Correcting Mathematical Errors Admitted

Posted on December 17, 2024 by Expert Witness Profiler

Plaintiff Kimberly Allcorn filed a lawsuit to recover damages for injuries from a collision with a tractor-trailer. Defendant Kay Beach, driving the tractor-trailer, worked for Western Flyer Express, LLC at the time.

Both vehicles traveled northbound on a four-lane highway with a 65-mph speed limit. Allcorn was in the right lane ahead of Beach, who was in the left lane at 71 mph. As Allcorn changed lanes, moving slower than Beach, the tractor-trailer struck the rear of Allcorn’s vehicle despite applying the brakes.

There was a fact dispute as to whether Beach, had she been driving the speed limit, could have avoided the collision. On June 10, 2024, Allcorn designated [Soan Chau](https://expertwitnessprofiler.com/expert-witness/Hung-Chau/1538222) as an accident reconstruction expert witness. Chau’s report concluded that if Beach had driven 65 mph, she could have avoided the crash.

On July 9, 2024, the Defendants provided the testimony of their own accident reconstruction expert witness, who found errors in Chau’s calculations. It was alleged that Chau’s report misrepresented Beach’s speed as 76 mph instead of 71 mph and claimed that even at 65 mph, the crash would have been unavoidable.

On August 7, 2024, the Plaintiff submitted a corrected report from Chau. Chau maintained that Beach could have avoided the crash at 65 mph.

The Defendants requested the Court strike the report, arguing it was untimely and exceeded the scope for revisions. The Plaintiff claimed the report was both proper and timely.

## **Accident Reconstruction Expert Witness**

[Soan Chau](https://expertwitnessprofiler.com/expert-witness/Hung-Chau/1538222) is a transportation consultant specializing in vehicular accident analysis, with over 30 years of experience in cases involving passenger vehicles, tractor-trailers, motorcycles, bicycles, and pedestrians. Throughout his career, Chau has analyzed over a thousand cases, contributing expertise in scene preservation, documentation, surveying, reconstruction, simulation, animation, and other transportation-related matters.

Soan Chau earned a Bachelor of Science in Civil Engineering from the University of Florida in 1993. He further pursued advanced studies at the University of Florida, completing all required coursework for a Master of Science in Traffic Engineering between 1997 and 1999.

He is also a certified Event Data Recorder (EDR or “black box”) analyst and retriever for both commercial vehicles and passenger cars.

[Want to know more about the challenges Soan Chau has faced? Get the full details with our Challenge Study report.](https://app.expertwitnessprofiler.com/login?eId=1538222)

## **Discussion by the Court**

[Federal Rule of Civil Procedure 26(e)](https://www.law.cornell.edu/rules/frcp/rule_26) requires timely supplementation if a prior disclosure is materially incomplete or incorrect, and the information has not otherwise been provided during discovery. Additionally, under the present Court’s Local Uniform Civil Rule 26(a)(5), such supplementations must be made at appropriate intervals “and in no event later than the discovery deadline established by the case management order.”

The Court found no merit in the Defendants’ argument that supplementation is only required when based on new information unavailable at the time of the initial disclosure. Instead, Rule 26(e) clearly requires supplementation when a party learns of an error or omission, as occurred here.

The Defendants also argued that Chau’s supplemental report was unnecessary because their expert had already identified the errors. The Court held that this argument undermined the Defendants’ request for relief. If the corrections were already known, Chau had no obligation to provide them, and his supplemental report would have been gratuitous. However, the Plaintiff did not advance this position.

The Court concluded that once Chau learned of the errors in his calculations, he had a duty to correct them promptly. Chau complied with this duty by submitting a supplemental report within 30 days, well before the discovery deadline. The Court emphasized that Chau did not offer a new opinion disguised as a supplement. Instead, he corrected mathematical errors in his calculations without altering his opinion.

The Court found nothing improper in Chau’s actions, as his supplemental report adhered to both the letter and spirit of Rule 26(e).

## **Held**

The Court denied the Defendants’ motion to strike the supplemental report of Plaintiff’s accident reconstruction expert witness Soan Chau.

## **Key Takeaway:**

The Court admitted Soan Chau’s supplemental report, emphasizing the importance of timely corrections when an expert discovers errors in their calculations. Under Federal Rule of Civil Procedure 26(e), experts are required to correct any material inaccuracies in their disclosures, even if no new information is introduced.

The Court found that Chau’s corrected report, submitted within the required timeframe, was a necessary and appropriate response to the identified errors. Importantly, the Court noted that Chau’s supplemental report did not offer any new opinions but merely corrected mathematical errors without altering his original conclusions. In conclusion, the Court held that Chau’s actions complied with the letter and spirit of the Rule, denying the Defendants’ motion to strike the report.

Please refer to the blog previously published about this case:

[Physical Medicine & Rehabilitation Expert Witness’ Testimony Indicating a History of Post-Concussive Syndrome Deemed Speculative](https://expertwitnessprofiler.com/physical-medicine-rehabilitation-expert-witness-testimony-indicating-a-history-of-post-concussive-syndrome-deemed-speculative)

## **Case Details:**

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