People will recall different things after a truck accident. Maybe one person says the truck driver hit their brakes before impact and another says he did not. Maybe someone thought the truck was going a certain speed. There are tire marks and damage that can give you answers too. A truck’s data can give you information as well that may not have been witnessed.
There are two pieces of data that many people lump together. They can both be found in a truck but are used for different reasons. A truck black box may provide data on how a truck acted during or leading up to an incident. An Electronic Logging Device (ELD) can provide data on a driver’s driving time and duty status.
Knowing this will allow you to better understand how to utilize truck accident data.
Below are the main points:
- Truck Black Box Data
- Information obtained from ELDs
- How to create and corroborate a timeline
- The importance of obtaining these files
What a Truck’s Black Box Can Show
Not all trucks have one black box. There may be multiple computers in the engine, braking system and so on. Each may have data that can be pulled if there was an event that stored that information.
Speed, RPM, throttle position, brake switch engaged, etc. may be available to you depending on the truck. This can be helpful when trying to determine what the truck was doing prior to the vehicle decelerating or accelerating.
Keep in mind that an event may have been triggered due to the truck applying its brakes, not from the collision. The length of an event, data that is stored, and what causes an event to be stored varies between trucks.
You may only get information around the time that an event was triggered, not throughout the trip. You will want to know what the event length and trigger is before incorporating this data into your timeline.
ELD Logs Tell the Longer Story
ELD data can show the driver’s recorded duty status and driving activity, but not everything the driver did on duty.
As of recent years, an ELD will record duty status, date, time, engine hours, vehicle miles, and location of the truck. You can cross reference what a driver states they were doing with this data.
If a driver has recorded rest time, you can not say that they were sleeping. Location points will also not give you an accurate depiction of the entire trip. When a truck is rolling, location points will be recorded at certain intervals, including hour by hour.
It’s important to know what each piece of data is capable of when requesting files from a trucking company. If you’re working on a truck accident claim in Houston, Texas, Pierce Skrabanek can help you obtain and utilize this information.
Something to note is that there is no requirement for an ELD to store speed, brake or steer data. Trucks can record this data, but they will not always be connected to the ELD.
Putting Separate Records on One Timeline
This is where data becomes useful in truck accidents.
If a driver stated that they stopped before arriving at their final destination, you may see that they changed their duty status on their ELD. By looking at the miles, you can also see if the truck drove more miles after the driver went on break and figure out why the truck may have driven additional miles.
All of this data should not be used by itself. The truck may have made a drive that was allowed, maybe they drove somewhere after that or you will have to ask the driver to explain that entry.
Once you get closer to the accident, you may see deceleration from the truck’s black box, or even a brake switch being applied. Correlate this data with any video that may be available to see if others in traffic are acting similar to the truck’s movements. Use skid marks and damage to help establish where the vehicles made contact.
One thing to keep in mind is that there may be two clocks, one from the black box and one from the ELD. Make sure to correlate these times before you incorporate both into your timeline. Also, know that time zero on an event data download may not correspond to the initial collision.
In one NTSB investigation, the truck’s recorded time zero marked its later impact with a concrete barrier and/or crash attenuator, after it had already struck an SUV.
The Insurance Institute for Highway Safety reports that 5,340 people died in U.S. crashes involving large trucks in 2024. Knowing what each piece of data can do will help you create a reliable reconstruction of a crash.
Why Preserving the Right Files Matters
Not all electronic files are created equally.
Some events may overwrite data that is currently on a truck’s computer. If there are cameras on the truck, they may be on a looping system. You will want to make sure that the proper files are preserved. Sometimes you will need to have a data expert recover information from a computer, or even pull the truck apart to get that information.
Federal rules generally require motor carriers to retain ELD records of duty status and supporting documents for six months. That period does not guarantee that black-box files, camera footage or other electronic evidence will remain available for six months.
You also have the ability to see any edits that have been made to an ELD. If there was an edit made, that does not mean something was done improperly, it could have been fixed.
If you’ve been involved in a truck accident, make sure that your preservation letter requests the correct files. Once you have identified what truck was involved and when, you can ask for the proper data that you feel will be beneficial in your case. You may have to take additional measures to obtain this data, but at least you know what to ask for.
Remember to find out who holds the information and what type of data that may be available before a truck is put back on the road.
A Download Still Has to Be Checked
Just because you have data from a truck, doesn’t mean everything on it is accurate.
After obtaining a download, you will want to ensure that the file corresponds to the truck you are requesting information from. After that, you will want to know if the truck can provide this type of data.
As mentioned above, some trucks can calculate the speed that the truck was traveling based off of tires/drivetrain. If the tires are not the right size, or the truck was sliding, this number may not be 100% accurate. Brake switches may show if the switch is engaged, but it does not always tell you how hard the truck was braking.
There are many variables that can affect the data on a truck, but here are some things to keep in mind when analyzing a download:
- Is this data from the truck and event being examined?
- Can this download be correlated to the time of the accident, based on video or other evidence?
- What kind of equipment was the truck running that may affect the download?
Once you have these answers, you can start correlating this download with what others saw, images, and damage to the vehicles.
What the Data Can Settle, and What It Can’t
As you can see, truck black boxes can provide you with information that may help prove that a truck accelerated or decelerated prior to a crash. ELDs can help you determine if a driver was on or off duty, and for how long. However, there are many things that cannot be determined from these downloads.
If you had a download that showed no brake switch applied until just before the accident, you could assume that the driver did not react to the situation in time, but what about what the driver may have seen, another vehicle may have cut them off, or their brakes may not have functioned properly.
The truck’s data can support a theory, challenge a witness account, or narrow the possible sequence of events. Other evidence is still needed to test those explanations.
Putting the Pieces Together
There are many things that can be obtained from truck black boxes and ELDs, and will continue to grow as technology advances. Utilize each piece of data to its fullest extent, and you will have a great chance of accurately recreating what happened.