November 6, 2026
After a commercial truck crash, the trucking company has a head start. Its insurer may have investigators on the scene within hours. Meanwhile, you or your loved one may be in a hospital bed, focused on getting through the next day.
Evidence showing what happened in the seconds before impact does not wait for you to recover. Much of it is time-sensitive. Some records have federal minimum retention periods of months. Others have no protection. For example, footage from a gas station camera pointed at the intersection may be recorded within days. Spoliation usually starts in the gap between how long evidence actually lasts and how long people assume it lasts.
For decades, the truck accident attorneys at The Cochran Firm have held trucking companies accountable when they cut corners, including by letting critical evidence disappear. For the general rules on what counts as evidence and when a court will allow it, see our guide on what is evidence and when it is relevant.
In This Article:
Spoliation of evidence is the destruction, alteration, or loss of evidence that a party had a duty to preserve because a lawsuit was pending or reasonably foreseeable.
In trucking cases, spoliation takes two forms. They look the same from the outside, but courts treat them very differently.
The duty to preserve evidence does not wait for a lawsuit. Federal Rule of Civil Procedure 37(e) is based on a long-standing common law obligation: once litigation is reasonably foreseeable, a party must preserve relevant information. The rule's advisory committee notes clarify that Rule 37(e) does not create this duty but assumes it already exists.
When litigation becomes foreseeable depends on the facts. Courts consider what the company knew or should have known. A serious injury crash involving its own tractor puts a carrier on more notice than a minor collision. A written preservation demand removes any doubt. That is why carriers are expected to pause automatic deletion and secure black box data before the truck returns to service.
The black box is the type of evidence most people have heard of, and it has the least protection. No Federal Motor Carrier Safety Administration (FMCSA) rule sets a retention period for engine control module (ECM) data.
The ECM stays on the tractor, and many systems store only a limited window of events. Continued driving can overwrite that data. If the trucking company repairs the tractor and puts it back into service, the clock keeps running. That is why the ECM is usually one of the first things our attorneys move to secure, often through an agreed inspection and forensic download.
Electronic logging devices (ELDs) track a driver's hours of service. Federal rules protect this data more than ECM data, but the protection is still limited:
Read the six-month figure carefully. It is a regulatory minimum, not a destruction date. A carrier may keep records longer, but nothing in federal rules guarantees they will exist when your case needs them.
Other trucking records run on their own clocks, and those clocks don't match:
| Evidence | Who Holds It | What the Rules Require | What Is Lost If It Goes |
| Records of duty status (driver logs) and supporting documents | Motor carrier | At least 6 months from date of receipt, under 49 CFR 395.8(k)(1) | Hours the driver worked before the crash |
| Backup copy of ELD records | Motor carrier | 6 months, on a device separate from the original, under 49 CFR 395.22(i)(1) | The second copy, if originals are edited or lost |
| Engine control module (ECM) data | Motor carrier, on the tractor | No federal retention period | Speed, throttle, and braking in the final seconds |
| Driver vehicle inspection reports | Motor carrier | 3 months from the date prepared, under 49 CFR 396.11(a)(4) | Defects the driver reported before the crash |
| Roadside inspection reports | Motor carrier | 12 months from the inspection, under 49 CFR 396.9(d)(3)(ii) | Out-of-service history and prior violations |
| Maintenance and repair records | Motor carrier | 1 year, and for 6 months after the vehicle leaves the carrier's control, under 49 CFR 396.3(c) | Brake, tire, and repair history on the tractor |
| Accident register | Motor carrier | 3 years after each accident, under 49 CFR 390.15(b) | Whether this crash fits a pattern |
| Driver qualification file | Motor carrier | Length of employment plus 3 years, under 49 CFR 391.51(c) | Hiring, training, and violation history |
| Third-party surveillance or dashcam footage | A business, homeowner, or another motorist | No rule requires anyone to keep it | Often the only neutral view of the collision |
No federal trucking rules cover camera footage held by businesses, homeowners, or other drivers. These rules only apply to motor carriers.
Cameras at stores, loading docks, homes, and on traffic poles usually record over old footage on a set schedule. Depending on the system, this footage might be gone in just days or weeks. Dashcam videos from other drivers can be lost even sooner if no one asks for them.
This footage is often the only unbiased record of the crash. Unfortunately, it is also the evidence most often lost simply because no one requested it soon enough. Its own cameras are different. Once litigation is reasonably foreseeable, the carrier's duty to preserve covers that footage just as it covers driver logs and ECM data. When a government agency holds the video, the rules change again.
An evidence preservation letter, also known as a spoliation letter, is a written request asking someone to identify and keep certain evidence and to stop any routine process that might destroy it. A preservation letter is not a court order and does not require anyone to turn over evidence. Instead, it sets a clear notice date. If evidence goes missing later, the date of the letter may help show when the other side was on notice.
You should send a preservation letter to more than just the trucking company. It should also go to:
Third parties are not required to preserve evidence the same way a carrier is. Still, sending a letter quickly is often the best way to keep footage from being erased.
A good preservation letter is specific, not generic. Instead of asking for "all relevant records," it should list each type of evidence you want preserved:
Many people are unsure what happens when evidence gets destroyed. That’s why it’s important to explain things clearly.
Rule 37(e) covers electronic information if three things are true: the party should have kept it, they lost it because they didn’t take reasonable steps, and it can’t be restored or replaced by other means. If these conditions are met, the court has two main choices.
If the court decides the loss hurts the other side, it can order steps to fix the problem, but only as much as needed. These steps might include:
The strictest penalties apply only if the court finds the party meant to keep the other side from getting the information. These penalties include presuming the lost information was unfavorable to the party that lost it, instructing the jury that it may or must presume the same (an adverse inference instruction), and dismissing the case or entering a default judgment.
Proving intent is a real challenge. When the current version of the rule started in 2015, the advisory committee made it clear that adverse inference instructions cannot be given for negligence or gross negligence alone.
Will the judge tell the jury to hold the trucking company responsible for destroyed evidence? The court could, but only if it finds there was intent to hide information. Missing data alone isn’t enough. Proving this takes lawyers who know what to ask for, when to ask, and how to show what the company knew.
Review our truck accident checklist for more scene-level details.
There’s no federal rule for how long engine control module data must be kept. Under 49 CFR 395.8(k)(1), driver logs must be kept for at least six months. ECM data depends on the company’s own rules and the device’s limits, and it can be erased as the truck keeps running.
Before a duty to preserve attaches, a carrier that destroys records under its retention schedule and federal minimums is generally within its rights. Once the duty attaches, courts treat continued destruction of relevant evidence as spoliation.
A preservation letter is a written request to keep certain evidence and stop regular deletion. A lawyer usually sends it to the trucking company, its insurer, and anyone else who might have footage or physical evidence. This letter sets an official notice date.
Not automatically. Under Rule 37(e)(2), a federal court may give an adverse inference instruction only if it finds the company intended to deprive the other side of the information. If the loss was careless rather than intentional, the court may still order measures under Rule 37(e)(1), which can include letting the jury hear about the loss.
Not necessarily. Retention periods vary by record type, and some records must be kept for years. Data that looks lost can sometimes be recovered from a telematics vendor, an insurer's early investigation, or a repair facility.
Trucking companies and their insurance companies start looking out for themselves right after a crash. You deserve a legal team that works just as hard for you, and just as quickly.
At The Cochran Firm, our truck accident attorneys combine local representation with the resources of a national firm. We move quickly to send preservation demands, secure black box and ELD data, and track down footage before it disappears. We charge no fees unless we recover compensation for you.
If you or someone you care about was hurt in a crash with a commercial truck, call 1-800-THE-FIRM or contact us online for a free consultation. We’re here for you 24/7.
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