What counts as a maintenance failure in a truck accident case?

A maintenance failure is a mechanical problem that a carrier should have caught or fixed through routine inspection and repair, such as worn brake linings, tires below the legal tread depth, a cracked wheel, or a steering or suspension defect. These differ from sudden, unforeseeable part failures because they usually leave a paper trail of missed or deferred maintenance in the truck's own records.

Who is responsible for keeping a commercial truck properly maintained?

The motor carrier that controls the truck is responsible for systematically inspecting, repairing, and maintaining it, along with the drivers who complete daily inspection reports. Responsibility can extend to a leasing company or a separate maintenance contractor if that party actually handled the truck's upkeep, so identifying every party involved in maintaining the vehicle is part of investigating the claim.

Can a passed inspection still mean the carrier was negligent?

Yes. An annual inspection reflects the truck's condition on a single day, not a promise that nothing will fail afterward. A carrier that skips a recommended repair, ignores a driver's inspection report, or lets a known issue go unaddressed after a passing inspection can still be negligent for what happened later.

How can an attorney get a trucking company's maintenance records?

An attorney typically starts with a written request or preservation letter to the carrier and its insurer, then uses formal discovery, including subpoenas, if the carrier does not produce the records voluntarily once a lawsuit is filed. Because federal law only requires carriers to keep these records for a limited time, requesting them without unnecessary delay improves the chances they still exist.

Truck Black Box Data After an Accident in Colorado

A trucking company’s account of a crash is not the only version of events. Buried inside most commercial trucks’ engine control module is a record of what the truck itself was doing in the moments before impact: speed, braking, throttle position, and more, depending on the system. That data can confirm or contradict what the driver says happened, but it is not preserved automatically, and no federal rule guarantees it will still exist by the time your claim is underway.

Elkus & Sisson, P.C. secures and analyzes black box and engine control module data for injured clients across Colorado, working to identify what a specific truck’s system recorded and to preserve it before it can be lost, as Colorado truck accident attorneys.

What Is Truck “Black Box” Data

Most passenger cars record crash data through a dedicated airbag control module. Heavy trucks generally do not have airbags in the same way, so event recording is typically built into the engine control module (ECM) instead. Rather than using the same accelerometer-based triggers as a passenger car, heavy-truck systems commonly identify a recordable event using a hard-brake or sudden-deceleration threshold. Some trucks also store event data in separate chassis or safety-system modules, so the “black box” is often not a single device, and what it captures depends on the make, engine, and system installed.

A mechanic measures tire tread depth on a commercial truck during a maintenance inspection in Colorado.

What the Data Can Show

Depending on the specific vehicle and system involved, ECM data may include:

Vehicle speed in the moments before and after a triggering event
Braking application and hard-brake events
Throttle position and engine RPM
Fault codes and diagnostic data, such as low oil pressure or engine over-speed conditions
Time stamps and engine hours, which can help correlate the event to the crash

Not every system records the same information, and some do not capture crash-related speed or braking data at all. Identifying exactly what a specific truck’s system is capable of recording is one of the first steps in a black box investigation, not an assumption made in advance.

Why This Data Is at Risk

The federal event data recorder rule, 49 C.F.R. Part 563^[1], applies only to specified passenger cars, multipurpose vehicles, trucks, and buses at or below certain weight limits, and does not apply to large commercial trucks outside those limits. There is no equivalent federal rule requiring a heavy truck’s ECM or event data to be preserved for any set period after a crash. The industry’s own voluntary standard, SAE J2728, a recommended practice for heavy-vehicle event data recorders^[2], does not create a legal preservation mandate either. That absence of a retention rule matters because of how this data is actually stored. Some systems retain only a limited number of recent events, such as the last two hard-brake records, and can overwrite older data when a new qualifying event occurs^[3], which can happen simply by continuing to operate the truck after the crash. Data can also be lost through severe physical damage to the module, loss of electrical power, or improper handling during repairs or an uncoordinated attempt to extract it.

Spoliation Risk and Colorado Law

Even without a federal retention mandate, a trucking company is not necessarily free to let this data disappear. The Colorado Supreme Court held in Terra Management Group, LLC v. Keaten, 2025 CO 40^[4] that a duty to preserve relevant evidence arises when a party knows or should know that litigation is pending or reasonably foreseeable, an objective, fact-specific standard. A written preservation request sent early in a claim can help establish that the carrier was on notice of that duty before any data went missing.

How an Attorney Secures Black Box Data

Securing this data is usually a coordinated legal and technical process: a written preservation request identifying the specific truck and systems at issue, followed by formal discovery once litigation is filed if the carrier does not produce the data voluntarily, and a qualified forensic expert to properly image and interpret whatever the system actually recorded. Our evidence after a truck accident page covers how this preservation and discovery process works in more detail. Black box data rarely tells the whole story by itself. Reviewed alongside a driver’s hours-of-service violations history and the broader question of driver fatigue, it can help build a fuller picture of what a driver was doing, and how long they had been doing it, in the period leading up to the crash. Colorado generally gives you three years from the date of the crash to file a personal injury or property damage claim, C.R.S. § 13-80-101(1)(n)^[6]. Wrongful death claims follow a separate, shorter deadline, generally two years under C.R.S. § 13-80-102^[7], with a narrow exception extending it to four years where the driver is convicted of vehicular homicide and left the scene, so families should confirm the applicable deadline with an attorney as soon as possible. Any documented negligence this data helps establish is measured under Colorado’s comparative negligence law, C.R.S. § 13-21-111^[5].

Frequently Asked Questions

What is "black box" data in a commercial truck?

Unlike passenger cars, most commercial trucks do not have airbags or a dedicated airbag control module. Instead, event recording is typically built into the truck’s engine control module (ECM), which can detect a hard-brake or sudden-deceleration event and store a data snapshot around it. Some trucks also record event data through separate chassis or safety-system modules, so “black box” data is not always a single device.

What can black box or ECM data show about a truck accident?

Depending on the vehicle, engine, and recording system involved, ECM data may show speed, braking, throttle position, engine RPM, and other parameters around the time of the crash. Not every system records the same information, and some do not capture crash-related speed or braking data at all, which is why the specific system involved has to be identified before assuming what it recorded.

Is there a law requiring trucking companies to preserve black box data?

There is no federal regulation requiring a heavy truck’s ECM or event data to be preserved for any set period after a crash. The federal event data recorder rule, 49 C.F.R. Part 563, applies only to lighter passenger vehicles and does not cover large commercial trucks. Separately, Colorado law can require a carrier to preserve relevant evidence once litigation is pending or reasonably foreseeable, regardless of whether a federal retention rule exists.

How quickly can black box data be lost after a truck accident?

It depends on the system and what happens to the truck afterward. Some systems store only a limited number of recent events and can overwrite older data when a new hard-brake or similar event is triggered, which can happen simply by continuing to operate the vehicle. Data can also be lost through severe damage to the module, loss of electrical power, or improper handling during repairs. There is no fixed timeline, which is part of why early action matters.

Can black box data be used to prove a driver was speeding or fatigued?

It can be part of that case, though rarely the whole case on its own. Speed and braking data around the time of impact can support or contradict a driver’s account of the crash, and can be reviewed alongside hours-of-service records and driver logs to build a fuller picture of what happened, including whether fatigue or a hours-of-service violation played a role.

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Talk to a Colorado Truck Accident Attorney About Black Box Data

Black box and ECM data can be overwritten by continued use of the truck, including a single additional hard-brake event, or lost through damage, power loss, or improper handling during repairs. Contact us promptly to help preserve it. From its Greenwood Village office, Elkus & Sisson, P.C. represents injured drivers and families across Denver, Greenwood Village, Lakewood, Aurora, and Boulder in personal injury matters including truck accident claims, trucking company liability, catastrophic injury, and wrongful death.

If you have questions about black box data in a Colorado truck accident, contact us or call +1 303-567-7981 to schedule a confidential consultation.

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