Two drivers walk away from an intersection collision on Rainbow Boulevard with completely different stories. One says the light was green and the other was doing at least fifty. The other says the light had just turned, and nobody was speeding. There are no independent witnesses, the intersection camera is a traffic sensor rather than a recorder, and the police report lists both accounts without picking one.
That case looks like a coin flip until somebody pulls the data off the vehicles. Modern cars carry an event data recorder that captures speed, throttle position, brake application, seat belt status and the change in velocity during the crash itself. Heavy trucks carry an engine control module that holds even more. Neither one is impressed by anyone’s version of events, and in a disputed liability case that objectivity is often the difference between a denial and a settlement.
The catch is that this evidence is legally protected, physically fragile and easy to lose. Here is what the black box in a Nevada crash actually records, who owns it under federal and Nevada law, and how the download gets made before the data is gone.
What an Event Data Recorder Actually Captures
An event data recorder, usually called an EDR, is not a flight recorder and it is not always running. It buffers a rolling window of vehicle data and writes that window to memory when a triggering event occurs, typically an air bag deployment or a comparable impact. Outside of those events, nothing is stored.
The federal rule that standardizes the output is 49 CFR Part 563. Its stated purpose is to make sure EDRs record data useful for crash investigation and safety equipment analysis in a readily usable form, and to require manufacturers to make tools or methods commercially available so crash investigators and researchers can retrieve it.
Part 563 requires a set of data elements from every covered vehicle equipped with an EDR. The list includes longitudinal delta-V, which is the cumulative change in velocity along the vehicle’s front to back axis during the impact, the maximum delta-V and the time at which it occurred, indicated vehicle speed before impact, engine throttle or accelerator pedal position as a percentage of full, service brake status recorded as on or off, ignition cycle counts at the time of the crash and at the time of download, driver safety belt status, air bag warning lamp status, air bag deployment timing for the driver and right front passenger, and a count of multiple events with the interval between them.
The vehicle’s owner manual has to carry a plain language notice about all of this. Under section 563.11 the manual must state that the vehicle has an EDR, that its purpose is to record data in certain crash or near crash situations, that it typically holds 30 seconds or less of information, and that it records items such as how the vehicle’s systems were operating, whether the belts were buckled, how far the driver was pressing the accelerator or brake, and how fast the vehicle was traveling.
The Recording Window, and What Is Changing
The most valuable part of an EDR download in a liability fight is usually the pre-crash data, the seconds before impact that show speed, throttle and braking. For most vehicles on the road today that window is short, roughly five seconds sampled twice per second.
That is changing. A federal rule published on December 18, 2024 amended Part 563 to expand pre-crash capture from 5 seconds at 2 samples per second to 20 seconds at 10 samples per second, a fourfold increase in duration and a fivefold increase in resolution. The compliance schedule has since moved. A final rule published on May 18, 2026 adopted a four year phase-in beginning September 1, 2028, with 25 percent of a manufacturer’s applicable vehicles produced between September 1, 2028 and August 31, 2029 required to meet the amended requirements.
The practical takeaway is that the expanded window is coming but is not here yet for the vehicle in your crash. Treat the pre-crash record as a handful of seconds, and understand that those seconds usually end at impact rather than covering the approach.
Coverage matters too. Part 563 applies to vehicles manufactured on or after September 1, 2012, if they are equipped with an event data recorder, and reaches passenger cars, multipurpose passenger vehicles, trucks and buses with a gross vehicle weight rating of 3,855 kilograms, or 8,500 pounds, or less. The rule standardizes what a recorder must capture when one is installed. It does not require every vehicle to have one, and heavier commercial vehicles fall outside its scope entirely.
The Bigger Box in a Commercial Truck
A tractor trailer is a different evidence problem, and usually a richer one. Heavy trucks carry an engine control module, or ECM, that manages the engine and logs operating data over far longer periods than a passenger car EDR. Depending on the engine manufacturer and configuration, an ECM download can produce records of hard braking events, a last stop record, road speed and engine speed histories, cruise control status, and fault codes with timestamps.
Trucks also generate a paper trail no car produces. Federal hours of service rules require electronic logging, and 49 CFR 395.8 requires a motor carrier to retain records of duty status and supporting documents for each of its drivers for not less than six months from the date of receipt, while the driver must keep the previous seven consecutive days available for inspection while on duty.
Six months is short. In a case where the injured person spends the first several months in treatment before consulting anyone, the logs that would show a driver in hour fourteen of a shift can be gone before the claim is even filed. That is the single strongest argument for sending a preservation demand to a motor carrier within days rather than months. Our semi truck crash practice and our broader truck accident practice both start from that premise.
Who Owns the Data Under Federal Law
Congress answered the ownership question in the Driver Privacy Act of 2015, enacted as part of Public Law 114-94 and codified as a note to 49 U.S.C. 30101. Any data retained by an event data recorder is the property of the owner of the motor vehicle, or of the lessee in the case of a leased vehicle.
The statute then lists the circumstances in which someone other than the owner or lessee may retrieve the data. Access is permitted when a court or other judicial or administrative authority with jurisdiction authorizes retrieval, subject to that body’s rules on admission of evidence. It is permitted with the written, electronic or recorded audio consent of the owner or lessee. It is permitted in certain federal investigations, with limits on disclosure of identifying information. It is permitted where retrieval is necessary to facilitate emergency medical response following a crash. And it is permitted for traffic safety research, provided that personal identifiers and the vehicle identification number are protected.
Two consequences follow. If the data you need is in your own vehicle, you can authorize the download yourself. If the data you need is in the other driver’s vehicle, you need that person’s consent or an order, and neither one shows up on its own.
Nevada’s Own Restriction on Pulling the Data
Nevada regulates the same subject independently. NRS 484D.485 defines an event recording device as a manufacturer installed device that records the direction and rate of speed at which the vehicle travels, records a history of where the vehicle travels, records steering or brake performance including whether the brakes were applied before a crash, records the status of the driver’s safety belt, or is able to transmit crash information to a central communications system.
The statute requires the manufacturer of a new motor vehicle to disclose the device in the owner’s manual. It then provides that data recorded by an event recording device may not be downloaded or otherwise retrieved by a person other than the registered owner of the vehicle, subject to specific exceptions. Those exceptions cover consent by the registered owner, an order of a court of competent jurisdiction, retrieval for motor vehicle safety research where the identity of the owner is not disclosed, retrieval by a dealer or repair facility for diagnosing or servicing the vehicle, and retrieval under a subscription service where the agreement discloses the capability. A violation of the section is a misdemeanor.
Nevada and federal law point in the same direction. The person who controls the vehicle controls the data, and everybody else needs either consent or an order. A defense-side investigator who quietly downloads the other vehicle without authority creates a problem, and so does a plaintiff-side one.
Getting the Download Without a Fight, and What to Do When There Is One
Cooperative downloads happen more often than people expect. In a case where both carriers want to resolve liability, a joint inspection with a qualified technician using the manufacturer approved retrieval tool, both sides present, and an agreement in writing about how the data will be handled, is faster and cheaper than motion practice.
When the other side refuses, the sequence is straightforward. Send a written preservation demand immediately, identifying the vehicle by year, make, model and vehicle identification number, and stating explicitly that the EDR or ECM data, the module itself, and the vehicle are not to be altered, repaired, sold or salvaged. Send it to the owner, the insurer, the tow yard and any body shop holding the vehicle. Then file suit and use a request for production to obtain the download, or a subpoena to reach the vehicle wherever it sits.
Three points of physical urgency. Salvage vehicles get auctioned and exported quickly. Repair work can overwrite or clear stored records. And in some vehicles, continuing to drive or cycle the ignition can push a recorded event out of memory as new ignition cycles accumulate. Speed is not a preference here, it is the whole ballgame.
The download itself should be done by a qualified technician using tools approved for that make, with the imaging report preserved and the chain of custody documented. A download performed carelessly by an untrained person can be attacked later, and defending that attack costs more than doing it properly the first time.
When the Data Disappears and Nevada Spoliation Law Applies
Sometimes the vehicle is crushed, the module is gone or the truck is back in service with the logs overwritten. Nevada law has a response.
In Bass-Davis v. Davis, decided in 2006, the Nevada Supreme Court drew a line between two situations. Where evidence is willfully destroyed with the intent to harm another party, a rebuttable presumption arises that the evidence would have been adverse, and the burden shifts to the party responsible. Where evidence is negligently lost or destroyed, a permissible adverse inference applies instead, on the reasoning that the risk the evidence would have been unfavorable should fall on the party responsible for losing it. The court tied the availability of that instruction to whether the party controlling the evidence had notice that it was relevant, which generally means notice that litigation was reasonably foreseeable.
Notice is what a preservation letter creates. A defendant who received a specific written demand naming the module and the vehicle, and then let the vehicle be scrapped, is in a very different position from one who never heard from anybody. That letter is the reason the spoliation argument exists later.
What the Numbers Can and Cannot Prove
A download is powerful evidence and it is not a verdict. Several limits are worth understanding before anyone builds a case around it.
Indicated vehicle speed is the speed the vehicle’s own systems reported, which can differ from true ground speed when tires are the wrong size, when a wheel is locked or spinning, or when the sensor input is disturbed. Delta-V measures the change in velocity during the impact, which is not the same as impact speed and is not the same as the speed either vehicle was traveling before the collision. Brake status is often recorded as a simple on or off flag, so a light touch and a panic stop can look identical. And the recorded window ends where it ends, which means the seconds before that window, where the decision that caused the crash was made, may not be captured at all.
None of that makes the data unhelpful. It means the data has to be interpreted by someone who understands the specific system, and it means the download works best alongside scene evidence, vehicle damage, and the physical record of where the vehicles came to rest. The strongest cases are the ones where the electronic record and the physical evidence tell the same story.
It is also worth remembering that the data can cut both ways. A download can confirm that the other driver was accelerating through a yellow, and it can also confirm that your client never touched the brake. A lawyer who wants the data has to be prepared for both answers, and that willingness is exactly what makes the request credible.
These questions come up most often in disputed liability collisions handled through our Nevada car accident practice, and they matter most in the cases with the largest stakes, including a wrongful death claim where the person who could describe the crash is no longer here. The deadline for acting is covered in our overview of the Nevada filing deadline, and Nevada law gives an injured person two years under NRS 11.190 to bring an action for injuries caused by the wrongful act or neglect of another. If you want the federal requirements in their original form, the full text of 49 CFR Part 563 is published in the electronic Code of Federal Regulations.
Acting Before the Record Is Gone
If liability is disputed in your crash, or the other driver’s account does not match what you remember, the electronic record may resolve it, but only if someone secures it quickly. The Bourassa Law Group offers a free consultation to review the crash, send preservation demands to the parties holding the vehicles and the logs, and arrange a qualified download where the data is available. There is no cost for that conversation and no obligation afterward.
This article is general information about Nevada and federal law and is not legal advice. Vehicle systems and recording capabilities vary by make, model and year, and what is available in a specific case depends on the specific vehicle.
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