Sources checked: September 28, 2026
A collision with an 18-wheeler can leave evidence in several places at once: on the roadway, inside the vehicles, at a towing yard, in a carrier’s computer systems, and with outside vendors. An injured person does not need to investigate all of that at the scene. The useful first steps are to get medical help, identify the vehicles and companies involved, and preserve what can safely be recorded before it changes.
This article provides general Louisiana information, not legal advice. The evidence, deadlines, and available claims depend on the crash date and the facts.
Begin With Safety and the Scene
Call 911, move out of traffic if that can be done safely, and accept needed medical care. Louisiana law requires immediate notice to the appropriate law enforcement agency after a crash involving injury, death, or more than $500 in property damage. Inside an incorporated city such as Baton Rouge, that notice goes to the local police department. The same law also requires drivers to exchange identifying and vehicle information. See La. R.S. 32:398.
If your condition permits, take a broad video of the scene before vehicles are moved. Then photograph the final vehicle positions, debris, tire marks, gouges, fluid trails, barriers, traffic controls, lane markings, construction, lighting, weather, and road conditions. Capture every side of each vehicle, not only the point of impact.
For the commercial vehicle, record the tractor and trailer license plates, unit numbers, USDOT number, company names, and door markings. A tractor and trailer may have different owners, and the carrier operating the trip may not be the company whose name is most visible.
Keep the original photo and video files. Cropping, filtering, annotating, or reposting them can strip metadata or create questions about what changed. If a passenger or witness created a file, note who made it and ask that person to retain the original.
Witnesses and Nearby Video Can Be More Valuable Than They First Appear
Collect witness names, phone numbers, email addresses, and where each person was standing or driving. Ask neutral questions about what they personally saw or heard. Do not coach a witness or ask anyone to adopt a conclusion about fault.
Look for nearby businesses, homes, traffic cameras, construction cameras, and vehicles with dashcams. A camera that did not capture the impact may still show traffic flow, a signal cycle, weather, or the truck’s movements moments earlier. Many systems overwrite footage automatically, so identifying the camera owner is often more urgent than debating the crash at the scene.
The Police Report Is a Starting Point, Not the Whole Proof
A crash report can preserve the location, vehicle and insurance information, witness names, roadway conditions, statements, citations, and an officer’s initial observations. Get the report number and the investigating agency’s contact information if possible.
The report does not automatically decide civil fault. The officer may not have witnessed the collision and may not yet have video, electronic truck data, maintenance records, or statements from every witness. A citation or diagram may matter, but it should be compared with the rest of the evidence. The absence of a citation does not establish that no one was negligent.
Review the report for objective mistakes such as an incorrect lane, passenger, vehicle owner, insurer, or witness name. Keep the documents that support a correction and use the agency’s established process.
Identify Every Company That May Hold Truck Records
Important records may be held by the motor carrier, truck owner, trailer owner, maintenance contractor, ELD or telematics vendor, shipper, broker, loading company, or towing yard. The Baton Rouge truck accident practice page explains why those business relationships can change the investigation.
A targeted preservation notice should identify the driver, tractor, trailer, date, route, and collision. Depending on the issues, it may cover ELD records and edit histories, supporting documents, dispatch messages, GPS and telematics, onboard video, engine-control data, inspection and maintenance files, driver qualification records, phone or communication records, bills of lading, cargo records, scale tickets, load tenders, and delivery instructions.
The records do not all have the same retention period. Under 49 C.F.R. 395.8(k), a carrier must retain required records of duty status and supporting documents for at least six months. Covered driver vehicle inspection reports and repair certifications have a three-month retention period under 49 C.F.R. 396.11. The vehicle maintenance records required by 49 C.F.R. 396.3 must generally be kept for one year and for six months after the vehicle leaves the carrier’s control. A carrier’s accident register is kept for three years under 49 C.F.R. 390.15.
Those minimum regulatory periods do not guarantee that every useful dashcam clip, vendor file, or event record will remain available. The separate guides to ELD data and truck evidence preservation explain what those sources can and cannot show. A preservation request is not a substitute for formal discovery, and it does not prove negligence by itself.
Preserve the Vehicles and the File History
A damaged car or truck can contain information about impact location, intrusion, restraint use, lighting, tire condition, and mechanical issues. Do not repair, sell, salvage, or destroy a vehicle before interested parties have a reasonable opportunity to inspect it. Keep tow records, storage notices, estimates, and photographs showing the vehicle’s condition and location.
For digital evidence, retain the original files and make a working copy. Record who obtained each file, when it was received, and where it has been stored. That simple history can be important if authenticity or completeness is later disputed.
Medical and Wage Records Prove a Different Part of the Case
Scene evidence addresses how the collision happened. Medical and financial records address what it caused. Describe symptoms accurately, tell providers how the collision occurred, and follow reasonable treatment instructions. If cost, transportation, scheduling, or another real problem creates a treatment gap, document it rather than trying to explain it from memory months later.
Keep discharge instructions, referrals, prescriptions, work restrictions, bills, mileage, and out-of-pocket receipts. A short factual log can record changes in sleep, walking, lifting, driving, concentration, household work, and help received. Repeated or exaggerated entries are less useful than specific observations tied to actual days and activities.
For wage loss, preserve pay stubs, schedules, time sheets, leave records, tax records, and employer communications. A self-employed person may also need contracts, invoices, calendars, expense records, and prior revenue information.
Avoid Creating New Evidence Problems
Do not guess about speed, distance, or timing in a recorded statement. It is better to say that you do not know than to supply a number that later conflicts with physical or electronic evidence. Read releases and record authorizations carefully before signing them, especially if they reach unrelated medical or employment information.
Do not threaten or manipulate a truck driver, witness, or company employee. Do not post crash photographs, medical updates, travel, or physical activity on social media. An insurance adjuster may collect information, but the adjuster is evaluating the insurer’s exposure and is not responsible for building the injured person’s evidence file.
The Incident Date Affects Fault and Filing Rules
For accidents on or after January 1, 2026, Louisiana Civil Code article 2323 bars recovery when the injured person is assigned 51 percent or more of the fault. A lower percentage reduces recoverable damages in proportion to that fault. Neutral evidence can therefore matter when a carrier argues that another driver followed too closely, changed lanes, sped, or failed to react.
For delictual actions arising on or after July 1, 2024, Civil Code article 3493.1 generally provides a two-year prescriptive period beginning when the injury or damage is sustained. Other rules or exceptions may apply. The lawsuit deadline can be much later than the date a video is overwritten, a truck is repaired, or a short-retention record cycles out.
Build the Timeline From Facts, Not Assumptions
The most useful early file usually combines the report number, scene images, truck and trailer identifiers, witness information, medical records, wage documents, tow and storage records, and insurance communications. From there, the next task is to identify the missing record holders and preserve the sources that may change. A complete investigation may later require subpoenas, formal discovery, inspection, reconstruction, or expert analysis, but those steps work best when the original evidence has not been lost.