Licensed in Louisiana, Texas, and Arkansas
Licensed in Louisiana, Texas, and Arkansas
The phrase “black box” covers two different things on a commercial truck, and the distinction matters. One is the engine control module, which records vehicle performance around an event. The other is the electronic logging device, which records the driver’s duty status and has to be backed up for six months under federal regulation. Both can settle questions that would otherwise come down to competing accounts.
Neither device was designed to help an injured person. They exist for engine diagnostics and for regulatory compliance, which is precisely why the data is difficult to argue with.
At Lukov Injury Law, we treat this data as a priority in Louisiana truck claims because of how quickly parts of it can disappear.
What follows covers what each device holds, what the rules say about keeping it, and where the limits are. Contact us today to talk through your crash and what data may still exist.
The engine control module is a component of the truck’s own systems. Its purpose is managing and monitoring engine performance, and event recording is a by-product of that function.
What a particular module captures depends on its make, model, and configuration, which is an important qualification. Modules are not standardized across manufacturers the way a regulatory record is.
That variability is why the answer begins with a different question: which module is fitted. It is a question of fact for the individual vehicle rather than something that can be stated in advance.
The electronic logging device is the regulated one, and that changes everything about how it behaves as evidence.
An ELD records the driver’s duty status, which feeds directly into the hours-of-service limits in 49 CFR 395.3:
Because the ELD is regulated, its retention is too. Under 49 CFR 395.22(i)(1), a motor carrier “must retain for 6 months a back-up copy of the ELD records on a device separate from that on which the original data are stored.”
That six-month floor sits alongside the separate requirement in 49 CFR 395.8(k)(1) that records of duty status and supporting documents be retained for not less than six months from the date of receipt.
Data availability is not uniform, and the differences determine what an investigation can still reach.
The last row is the one to watch. Engine module data has no regulatory retention floor at all, so its survival depends on whether the vehicle is repaired, returned to service, or scrapped.
A written request does not by itself obligate a carrier in Louisiana to hold on to any of this, so the practical protection is how quickly the question gets asked.
Used carefully, the two records answer different questions.
Duty-status data speaks to the hours worked before a crash, which bears on fatigue and on whether the federal limits were exceeded. Engine module data, where it exists and where the module captured it, speaks to what the vehicle was doing around the event.
Neither one assigns fault. They establish facts that fault is then argued from, which is a meaningful difference when an insurer describes a download as conclusive.
Data also has to be read alongside physical evidence:
Each either fits what the electronics suggest or it does not, and a conflict between the two is itself informative.
The carrier holds the regulated records, and the vehicle holds the module. Neither is in the injured person’s possession, which is the practical difficulty.
That is a structural feature of truck claims rather than an obstacle unique to any case. It is also why the sequence of a claim differs from a car claim, a point we take up under Louisiana 18-wheeler crash claims.
Louisiana sets a two-year prescriptive period for most personal injury claims, running from the day the injury is sustained. Every retention period above is shorter than that.
Under Civil Code article 2323 as amended by Act 15 of 2025, effective January 1, 2026, a person found 51 percent or more at fault recovers nothing, and a lower share reduces the award proportionally. Incidents before that date remain under the older pure comparative fault system.
That fault rule is why the data matters beyond establishing what happened. It also bears on where the fault percentage lands, and a percentage argued from recorded data is harder to shift than one argued from memory.
The regulated records last six months, and the engine module data has no fixed life at all, which makes this the part of a truck claim that cannot wait. At Lukov Injury Law, we go after both early and build the rest of the case around what they show.
Abby Lukov handles the download question herself, and the first conversation costs nothing. Call us today at 504-315-5056 to talk through your crash and what may still be recoverable.
Disclaimer: This article provides general information and should not be treated as legal advice. Laws change over time, and outcomes depend on the specific facts of each case. No attorney-client relationship is created by reading this article or contacting Lukov Injury Law LLC. For advice about your situation, contact a qualified attorney. Time limits apply to legal claims, so do not delay in seeking legal help.
The term covers two different systems. The engine control module is a component of the truck’s own engine management, and what it records varies by make, model, and configuration. The electronic logging device is separate, records duty status under the federal hours-of-service scheme, and behaves consistently because it is regulated.
It depends on which record is meant. Under 49 CFR 395.22(i)(1), a carrier keeps a backup copy of the ELD records for 6 months on a device separate from the one holding the original data. Engine control module data has no retention period set by regulation, so its survival depends on the module and on what happens to the vehicle afterward.
Duty status, which feeds into the hours-of-service limits in 49 CFR 395.3. Those limits require 10 consecutive hours off duty before driving, cap driving at 11 hours within a 14-consecutive-hour on-duty window, and require a consecutive 30-minute interruption once more than 8 hours of driving time have passed.
It establishes facts rather than assigning fault. Duty-status data can show whether federal driving limits were exceeded, and engine module data can show what the vehicle was doing around the event, but fault is argued from those facts alongside the physical evidence rather than decided by the download itself.
The records sit with the carrier, and the module sits in the vehicle, so neither is in an injured person’s possession. In Louisiana, a written request does not by itself obligate a carrier to hold on to anything, which is why raising the question early matters more than the request itself.
Engine control module data has no regulatory retention floor, so what happens to the vehicle can determine whether the data survives. Repair, return to service, or disposal can each affect availability. The regulated duty-status records are held by the carrier and follow their own six-month floor regardless of the vehicle.
They serve the same regulatory purpose of recording duty status. The retention requirements sit in separate provisions, with the ELD backup copy kept for six months under 49 CFR 395.22(i)(1) and records of duty status and supporting documents kept not less than six months under 395.8(k)(1).
Louisiana divides recovery by fault percentage, and under Civil Code article 2323 as amended by Act 15 of 2025, effective January 1, 2026, a person 51 percent or more at fault recovers nothing. Recorded data gives the fault argument something fixed to work from, which is harder to move than an account based on recollection.
