What is a truck's black box and how long is the data stored?

A truck's Electronic Control Module (ECM) or 'black box' records speed, braking, engine RPM, and other data from before and during a crash. Most systems overwrite data within 14 to 30 days, and some overwrite sooner if the truck is returned to service. An attorney must act immediately to preserve this data.

What is a spoliation letter in a truck accident case?

A spoliation letter is a formal legal demand sent to the trucking company requiring them to preserve all evidence related to the accident — including black box data, driver logs, maintenance records, dash camera footage, and the truck itself. Destroying evidence after receiving this letter can result in serious legal penalties.

How quickly should I hire a lawyer after a truck accident?

As soon as possible — ideally within 24 to 48 hours. Critical evidence like black box data, surveillance footage, and driver drug test results can be lost or destroyed within days. The trucking company's legal team begins working immediately after a crash, and you need an advocate doing the same.

Can a trucking company destroy evidence after an accident?

Intentionally destroying evidence after a crash can constitute spoliation, which carries legal consequences in Texas. However, without a formal preservation demand, companies may claim they disposed of records through routine business practices. This is why sending a spoliation letter immediately is critical.

First 72 Hours After a Truck Accident

Evidence in Truck Accident Cases Disappears Faster Than You Think

After an 18-wheeler crash on I-35, the Dallas North Tollway, or any road in North Texas, a clock starts ticking that most victims do not know about. While you are focused on your injuries and medical treatment — as you should be — the trucking company is already dispatching its rapid response team to control the narrative and, in many cases, make unfavorable evidence disappear.

The first 72 hours after a commercial truck accident are the most critical window for preserving the evidence that will make or break your case. Here is what happens behind the scenes and why immediate legal action matters.

The Trucking Company’s Rapid Response Team

Major trucking companies and their insurers maintain rapid response teams — sometimes called “go teams” — that deploy to serious accident scenes within hours. These teams are not there to help you. Their job is to gather evidence that protects the company, interview witnesses before your attorney can reach them, photograph the scene from angles that favor the carrier’s version of events, and begin building a defense before you have even left the hospital.

While you are recovering, the trucking company already has lawyers and adjusters working to minimize its exposure. You need an advocate working just as aggressively on your side.

Evidence That Can Disappear Within Days

The truck’s Electronic Control Module (ECM) data. Modern 18-wheelers are equipped with an onboard “black box” that records speed, braking patterns, engine RPM, seat belt usage, and other critical data from the moments before and during a crash. This data is stored on a loop. Many systems overwrite old data within 14 to 30 days — or even sooner if the truck is put back into service. Once overwritten, this evidence is gone permanently.

Electronic Logging Device (ELD) records. Federal law requires most commercial truck drivers to use ELDs to track their hours of service. These digital logs show when the driver was on duty, driving, or resting — and whether they violated federal limits. ELD data can be altered or “corrected” after the fact, and some carriers have been caught doing exactly that.

Dash camera and surveillance footage. Many trucks have forward-facing dash cameras, and nearby businesses may have security cameras that captured the crash. Businesses typically retain surveillance footage for only 7 to 30 days before it is automatically deleted. Without a preservation demand, this footage is lost forever.

The truck itself. Trucking companies may repair or scrap a damaged truck within days of an accident, destroying physical evidence of brake failure, tire defects, steering problems, or other mechanical issues that may have caused or contributed to the crash.

Driver drug and alcohol test results. Federal regulations require post-accident drug and alcohol testing of truck drivers in certain crash scenarios. If the trucking company fails to conduct timely testing — or if results are not properly preserved — critical evidence of impairment is lost.

Witness memories. Eyewitness accounts are most reliable immediately after an event. As days and weeks pass, memories fade, details become confused, and witnesses become harder to locate. Securing recorded statements early is essential.

What a Spoliation Letter Does and Why It Matters

One of the first things an experienced truck accident attorney does is send a spoliation letter — a formal legal demand requiring the trucking company, the driver, and any other relevant parties to preserve all evidence related to the accident.

A spoliation letter puts these parties on notice that a claim is being pursued and that destroying, altering, or failing to preserve evidence will have legal consequences. Under Texas law, a party that intentionally or negligently destroys evidence after receiving a preservation demand can face adverse inference instructions at trial — meaning the jury can be told to assume the destroyed evidence was unfavorable to the spoliating party.

This letter must go out immediately. Every day of delay is a day the trucking company can claim it “routinely” disposed of records in the normal course of business.

The Independent Investigation Your Attorney Should Conduct

A thorough truck accident investigation within the first 72 hours includes visiting the accident scene to document road conditions, sight lines, traffic signals, and any contributing environmental factors. It requires obtaining a certified copy of the police crash report with all supplements and witness statements. Your attorney should photograph and preserve the condition of all vehicles involved before they are repaired or scrapped. Downloading the truck’s ECM data before it is overwritten is critical, as is securing all dash camera, body camera, and nearby surveillance footage. Requesting the driver’s complete qualification file, medical certificates, drug test history, and driving record from the carrier provides essential background. Pulling the truck’s inspection and maintenance history to identify deferred repairs or missed safety issues rounds out the initial evidence gathering.

Do Not Wait to Contact an Attorney

The single biggest mistake truck accident victims make is waiting too long to get legal help. Every day you wait is a day that critical evidence may be lost. The trucking company is not waiting. Their legal team is working right now to protect the company’s interests — not yours.

At Ford Law, we begin our investigation immediately. Attorney Matthew Ford serves truck accident victims in Frisco, Dallas, Plano, McKinney, Allen, Prosper, and throughout North Texas.

Call (214) 227-9972 today for a free consultation. Available 24/7. No fee unless we win.

If you or a loved one was injured in a trucking accident, contact our North Texas trucking accident lawyers for a free consultation. Attorney Matthew Ford has the insider knowledge to fight for the compensation you deserve.