Obtain Truck Black Box Data Through Federal Discovery in the Northern District of Illinois

Truck black box data, stored in a semi’s engine control module (ECM) or event data recorder (EDR), can show the truck’s speed, braking, throttle, and cruise control in the seconds before a crash. Mixan Mahony, LLC represents people hurt in commercial truck crashes in Chicago and throughout Illinois. Many truck cases end up in federal court in the Northern District of Illinois, whose Chicago courthouse is the Everett McKinley Dirksen U.S. Courthouse at 219 South Dearborn Street. The short answer is that the data must be preserved first, then obtained through formal discovery: a Rule 34 request to a party, or a Rule 45 subpoena to a nonparty. Waiting can mean the data is overwritten.

How do I get truck black box data in a federal truck accident case?

Send an immediate preservation letter, then request the data in discovery. A party such as the trucking company can be served a request under Federal Rule of Civil Procedure 34, which covers electronically stored information. A nonparty, such as a leasing company or telematics vendor, can be served a subpoena under Rule 45.

What truck black box data can show

• Speed before and at impact.
• Brake application and its timing.
• Throttle and cruise control status.
• Hard-braking or sudden-deceleration events recorded automatically.
• Engine hours and fault codes, which can point to mechanical problems.

Truck black box data is often paired with telematics and GPS records, forward-facing camera video, and ELD logs. Together they can reconstruct a crash in detail. What a specific truck records depends on its make, model, and software, so an expert should handle the download.

Step one: preservation before discovery

Formal discovery cannot begin until a lawsuit is filed and the parties have conferred, but the data can be lost long before then. A written preservation (spoliation) letter should go to the carrier, its insurer, and any leasing company or telematics vendor as soon as possible. It should ask them to keep the tractor and its ECM unaltered, to stop any automatic overwriting, and to agree to a joint download by both sides’ experts. ELD records and supporting documents must be kept for at least 6 months (49 CFR 395.8(k)), and carriers may not alter or erase original ELD data (49 CFR 395.30(f)).

5 essential steps to obtain truck black box data in federal court

1. File in the right court. Federal courts may hear a truck case when the parties are from different states and the amount at stake exceeds the federal threshold, or when a case filed in state court is removed. Whether a case belongs in federal court is a legal question for counsel.
2. Serve a Rule 34 request on the carrier. Rule 34 lets a party request designated documents and electronically stored information in the other party’s possession, custody, or control. The request may specify the form of production, and if it does not, the data must be produced in the form in which it is ordinarily maintained or in a reasonably usable form (Fed. R. Civ. P. 34).
3. Use a Rule 45 subpoena for nonparties. Rule 45 lets a party command a nonparty to produce documents, electronically stored information, or tangible things, and the subpoena may specify the form for electronic data (Fed. R. Civ. P. 45). This is how data held by a lessor, telematics vendor, or repair shop is usually obtained.
4. Ask for native files and raw data. Printouts or summaries may leave out critical fields. Experts typically need the native download file.
5. Involve your expert early. An accident reconstruction expert can interpret the data and match it to the physical evidence.

Courts can impose remedies when relevant electronic information that should have been preserved is lost. What remedy applies is a legal question that depends on the facts.

The Northern District of Illinois

The U.S. District Court for the Northern District of Illinois has an Eastern Division in Chicago at the Everett McKinley Dirksen U.S. Courthouse, 219 South Dearborn Street, Chicago, IL 60604, and a Western Division in Rockford at the Stanley J. Roszkowski U.S. Courthouse, 327 South Church Street. Federal cases follow the Federal Rules of Civil Procedure and the court’s local rules.

The records every truck crash claim depends on, and how long they last

Trucking companies are required to keep many records, but often for short periods. These are the ones that matter most, with their minimum federal retention periods:

• ELD and hours-of-service records. Carriers must keep records of duty status and supporting documents for at least 6 months (49 CFR 395.8(k)) and may not alter or erase original ELD data (49 CFR 395.30(f)).
• Inspection, repair, and maintenance records. Carriers must keep these for 1 year where the vehicle is housed or maintained, and for 6 months after the vehicle leaves their control (49 CFR 396.3(c)).
• Driver Vehicle Inspection Reports (DVIRs). Carriers must keep the report, the repair certification, and the driver’s review certification for 3 months (49 CFR 396.11(a)(4)).
• Annual inspection reports. These must be kept for 14 months (49 CFR 396.21(b)).
• Driver qualification file. Carriers must keep one for each driver (49 CFR 391.51).
• Drug and alcohol testing records. Positive results and refusals are kept for 5 years, and negative results for 1 year (49 CFR 382.401).
• ECM/EDR downloads, telematics, and dashcam video. These can be overwritten when the truck returns to service and should be preserved immediately.

Because some of these windows are only months long, a preservation (spoliation) letter should go out right away. Our Illinois truck accident lawyers send those demands as soon as we are retained.

Layers of liability: who can be held responsible

Truck crashes usually involve several companies, each with its own insurance. Depending on the facts, responsible parties may include:

• The truck driver, for unsafe driving shown in the data.
• The motor carrier, for its driver’s conduct and any failure to preserve data.
• A leasing company or telematics vendor, which may hold data even if it is not at fault.
• A freight broker that negligently selected an unsafe motor carrier. The U.S. Supreme Court has held that federal law does not preempt this kind of state-law negligent-hiring claim, but the broker is liable only if the evidence proves it was careless in choosing the carrier.
• A shipper, in limited situations that depend on the facts and current law.

When more than one defendant is liable, all are jointly and severally liable for your medical expenses, and any defendant found 25% or more at fault is jointly and severally liable for your other damages (735 ILCS 5/2-1117). You can check a carrier’s public safety record, including its USDOT number and inspection history, on the FMCSA SAFER Company Snapshot.

Montgomery v. Caribe Transport II: can a freight broker be held responsible?

On May 14, 2026, a unanimous U.S. Supreme Court decided Montgomery v. Caribe Transport II, LLC, No. 24-1238, in an opinion by Justice Barrett. The case came from the Seventh Circuit, which covers Illinois, and the claim was brought under Illinois law. A truck driver was badly hurt when another semi struck his stopped tractor-trailer, and he sued the driver, the motor carrier, and the freight broker that arranged the load, claiming the broker knew or should have known from the carrier’s federal safety rating that hiring it was unsafe. The Seventh Circuit had ruled the broker claim was preempted. The Supreme Court reversed, holding that a claim that one company negligently hired another to transport goods falls within the safety exception of the Federal Aviation Administration Authorization Act (49 U.S.C. 14501(c)(2)(A)) and is not preempted. Read the Supreme Court’s opinion, the official docket, and the SCOTUSblog case page.

For people hurt in Illinois truck crashes, this means a negligent-selection claim against a broker can be brought alongside claims against the driver and carrier, whether the case is in the Circuit Court of Cook County at the Daley Center or in federal court at the Dirksen U.S. Courthouse. The ruling does not make brokers automatically liable. The injured person still has to prove that the broker failed to use reasonable care in choosing the carrier and that this failure helped cause the crash, and Illinois’ comparative fault rules still apply.

That is where the evidence in this article matters. A carrier’s FMCSA SAFER record, including its safety rating, out-of-service history, and inspection results, can show what a broker could have seen before it handed over the load. Black box data, ELD logs, and maintenance records can then show whether the same safety problems played out in the crash. Our Chicago truck accident lawyers handling freight broker claims request the broker’s carrier-vetting records and onboarding file along with the truck’s data.

Illinois’ 51% bar in truck crash cases

Trucking insurers often argue that the car driver cut in front of the truck, braked suddenly, or drove too fast. Illinois follows modified comparative negligence under 735 ILCS 5/2-1116: you are barred from recovering only if you are found more than 50% at fault, and any recovery is reduced by your percentage of fault. If truck black box data shows the truck was speeding and your damages are $500,000, a finding that you were 10% at fault would leave a $450,000 recovery.

How much insurance a trucking company must carry

Federal rules set minimum public liability coverage for interstate motor carriers (49 CFR 387.9). For-hire carriers hauling nonhazardous property in vehicles of 10,001 pounds or more must carry at least $750,000. The minimum rises to $1,000,000 for oil and many hazardous materials, and to $5,000,000 for certain bulk hazardous substances, explosives, and other high-risk cargo. These are minimums, not caps on what a company may owe. Many carriers also have excess or umbrella coverage, which is why identifying every policy matters.

What a truck black box data claim can include

Damages in a truck black box data claim can include past and future medical bills, lost wages and lost earning capacity, pain and suffering, disfigurement, and loss of normal life. Keep every bill, pay stub, and appointment record. In a serious crash, data showing excess speed or late braking can significantly affect how insurers value the case.

Insurers often make an early offer before the full extent of an injury is known. Before you accept anything in a truck black box data case, make sure your treatment has stabilized and every responsible party and policy has been identified. Our Illinois personal injury lawyers value each claim from the records, not from the insurer’s first number.

Deadlines

Federal courts hearing Illinois injury claims generally apply Illinois’ 2-year filing deadline (735 ILCS 5/13-202). A wrongful death action generally must be filed within 2 years after the death (740 ILCS 180/2(d)). Our Illinois truck accident lawyers begin preservation on day one. If a crash was fatal, our Illinois wrongful death lawyers can help.

What happens if a trucking company loses the black box data?

In federal court, Federal Rule of Civil Procedure 37(e) governs electronically stored information that should have been preserved but was lost. If the loss prejudices the injured party, the court may order measures to cure that prejudice. The harshest remedies, such as instructing the jury to presume the lost data was unfavorable or entering a default judgment, require a finding that the party acted with intent to deprive the other side of the information.

In Illinois state court, a defendant that negligently loses evidence can face a separate negligence claim for spoliation, as recognized in Boyd v. Travelers Insurance Co., 166 Ill. 2d 188 (1995). A written preservation letter sent early makes it much harder for a carrier to claim it did not know the data mattered.

ELD logs are not the same as the black box

The electronic logging device (ELD) records a driver’s hours of service, while the engine control module records speed, braking, and other vehicle events. Federal rules require motor carriers to keep records of duty status and supporting documents for six months (49 CFR 395.8(k)). A strong preservation letter asks for both, plus dash camera video, telematics, dispatch messages, and fuel and toll receipts that can confirm where the truck was and when.

Our Chicago truck accident lawyers send preservation demands as soon as we are retained, often within days of the crash.

Where Chicago-area truck black box data cases are filed

Venue in Illinois generally depends on where the crash happened and where a defendant resides or does business (735 ILCS 5/2-101). For crashes in the City of Chicago and much of Cook County, injury lawsuits are filed in the Law Division of the Circuit Court of Cook County at the Richard J. Daley Center, 50 W. Washington St. Suburban Cook County also has district courthouses in Skokie, Rolling Meadows, Maywood, Bridgeview, and Markham.

• DuPage County: 18th Judicial Circuit, Wheaton (Naperville, Downers Grove, Elmhurst).
• Lake County: 19th Judicial Circuit, Waukegan.
• Will County: 12th Judicial Circuit, Joliet.
• Kane County: 16th Judicial Circuit, Geneva (Aurora and Elgin).
• Winnebago County: 17th Judicial Circuit, Rockford.
• Federal court: the Northern District of Illinois at the Dirksen U.S. Courthouse, 219 S. Dearborn St., Chicago, with a Western Division in Rockford, when the parties are from different states and the claim exceeds $75,000.

Mixan Mahony, LLC represents clients from our downtown office at 444 W. Lake St., Suite 1707, in Chicago’s West Loop, and we work with families and injured people in Chicago, Evanston, Skokie, Oak Park, Cicero, Schaumburg, Arlington Heights, Des Plaines, Naperville, Aurora, Joliet, Elgin, Waukegan, Rockford, Springfield, Peoria, and Champaign, and across Illinois. We can meet by phone or video if travel is difficult.

How we handle your case

Every truck black box data consultation is free and confidential. We work on a contingency fee, which means no attorney fee unless we recover for you. Case costs, such as filing fees, records, and expert fees, are separate from attorney fees, and our written agreement explains exactly how they are handled before you sign anything.

Colleen Mixan Mikaitis and Mackenzie J. Mahony personally review new matters, and you will know who is working on your case and how to reach them.

Frequently asked questions

How long does a truck keep black box data?

It varies by truck and system, and data can be overwritten when the truck returns to service, so it should be preserved right away.

What is the difference between a Rule 34 request and a Rule 45 subpoena?

A Rule 34 request goes to a party in the lawsuit. A Rule 45 subpoena compels a nonparty to produce documents or electronic data.

Where is the federal court in Chicago?

The Northern District of Illinois sits at the Everett McKinley Dirksen U.S. Courthouse, 219 South Dearborn Street, Chicago.

Can a court punish a trucking company for destroying black box data?

Yes. In federal court, Rule 37(e) allows measures to cure prejudice from lost electronic data, and an adverse inference or default can follow if the court finds an intent to deprive. Illinois also recognizes a negligence claim for spoliation of evidence.

Is ELD data the same as black box data?

No. The ELD records hours of service, while the engine control module records speed, braking, and throttle data. Carriers must keep hours-of-service records for six months under 49 CFR 395.8(k), so both should be preserved quickly.

Can I sue the freight broker that hired the trucking company?

Possibly. In Montgomery v. Caribe Transport II, LLC (2026), the U.S. Supreme Court held that federal law does not preempt state-law claims that a broker negligently selected an unsafe motor carrier. You still must prove the broker was careless in choosing the carrier, for example by ignoring a poor FMCSA safety record, and that this contributed to the crash.

Lock down the black box data

The data that proves what a truck was doing can disappear quietly. Our Chicago personal injury law office sends preservation demands as soon as we are retained. Call us or tap for directions. If you have been injured in an accident, contact Mixan Mahony, LLC today for a free evaluation of your case.

Talk with a Chicago truck accident lawyer

Mixan Mahony, LLC
444 W. Lake St., Suite 1707
Chicago, IL 60606
Phone: (312) 262-3971
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This article is for general informational purposes and is not legal advice. Reading it does not create an attorney-client relationship.