TRUCK TALK
Modern Truck Technology
A commercial truck now writes a running record of the driver’s hours, the engine’s last seconds, the fleet’s GPS trail, and, on many rigs, video of the road and the cab. Paper logbooks used to be the only official account of a driver’s day, and they were easy to rewrite. In this Truck Talk segment, Jon Hollan walks through the systems that replaced those books, what each one actually captures, and why the whole stack has to be preserved after a crash rather than treated as a single device.
Paper Logbooks
For decades, truck drivers tracked hours in handwritten paper logbooks. A driver could keep two sets: one for an inspector, one that matched the hours actually driven. A carrier could press a driver to fill the “official” book after the fact, and there was little independent way to catch it. Investigators used to call those books comic books for a reason.
The harm showed up on the road. Fatigued drivers stayed out past legal limits, and driver fatigue became a leading contributor to serious truck crashes. When a crash happened, reconstructing the days before impact often depended on witnesses or luck, because the paper trail could be altered or thrown away. That is the record the later devices were built to replace.
Electronic Logging Devices
The Federal Motor Carrier Safety Administration required most interstate commercial drivers to use a registered electronic logging device by December 18, 2017. The device connects to the truck’s engine and records driving time when the vehicle is in motion. Driving status typically activates at 5 miles per hour. There is no paper substitute for a driver who is required to use one, and there is no off switch that lets the truck run off-record.
The hours themselves, the 11-hour driving cap, the 14-hour window, and the rest rules, belong to our Truck Talk episode on hours of service. This page is about the machine that writes those hours down. Under 49 CFR 395.26, as the Electronic Code of Federal Regulations records it, a registered ELD captures:
Date, time, and location
Stamped at regular intervals, so a claimed rest stop can be checked against where the truck actually sat.
Engine hours and vehicle miles
A running total tied to the engine, not to whatever the driver later writes down.
Duty status
Driving, on-duty not driving, off-duty, and sleeper berth, with each change logged.
Edits and annotations
Manual changes, the reason given, and who made them, which is the audit trail paper books never had.
Unassigned driving time
Movement of the truck with no driver logged in, a gap that often matters after a crash.
In a crash investigation, those logs can confirm or contradict a claimed rest period, show a dispatcher-enabled hours violation, and place the truck at a location at a given time. Carriers must retain records of duty status and supporting documents for six months under the FMCSA hours-of-service summary. That window is long compared with engine snapshots and camera loops, and it is still only a window.
Crash Event Recorders
The engine control module, often called the truck’s black box, answers a different question from the ELD. Hours data covers days. Event data covers seconds. The National Highway Traffic Safety Administration describes event data recorders as devices that capture information in the moments around a crash. On a commercial truck that snapshot commonly includes:
Vehicle speed
How fast the truck was traveling heading into the event.
Throttle and braking
Whether the driver was accelerating, and when and how hard the brakes were applied.
Engine RPM and cruise
Engine load and whether cruise control was engaged.
Stability and restraint data
ABS or stability-control interventions, and seat-belt status on some models.
Read with the ELD, that snapshot can show a driver who was speeding, late on the brakes, or running a truck that had already thrown fault codes. It does not live as long as the hours file. Event memory can be overwritten once the truck is repaired and back in service and another hard event is recorded. The download, the overwrite window, and how reconstruction experts use the file are the subject of our Truck Talk episode on black box data.
A preservation letter has to name the engine module while that record still exists. Destroying or allowing a named record to be overwritten after notice is spoliation, and Kentucky courts treat that as a serious discovery problem. The first-72-hour work of locking the truck and its electronics in place is covered in our Truck Talk episode on truck accident investigations.
Fleet Telematics
Beyond the ELD and the engine module, most large carriers now run telematics platforms that stream data in real time. Those systems sit at the carrier, and often at the shipper, and they watch the transportation cycle all day. Typical feeds include GPS location, speed, harsh braking, geofence violations, idling, and driver-behavior alerts. Harsh-braking and speeding events that never make it into the ELD’s required fields often live here.
When a platform showed a pattern of hard stops or speeding before a crash, and the carrier left that pattern alone, the file is evidence of how the company supervised the driver. Retention is not uniform. Some vendors keep 30 days. Some keep a year. A preservation demand that names only the ELD and the engine module can miss the telematics layer entirely. Fleet-management platforms that roll those feeds into one dashboard are covered in more detail on our page on fleet management system data.
Jon’s WKYT segment on this topic, “Big Data and Big Trucks,” is the reason this companion article exists. The point of the segment is not that computers made trucking safe. It is that the same computers now produce a record of fatigue, speed, distraction, and maintenance that used to disappear into a paper book.
Dashcam And In-Cab Cameras
Forward-facing and driver-facing cameras are now common on commercial fleets. A forward camera shows the road, the traffic, and the conditions at impact, and it can confirm or contradict a speed reading. An inward camera can show a driver on a phone, drifting, or nodding off. Many systems sync the clip to a telematics event, so a hard-brake alert and the video of that alert arrive as one file.
Camera footage is the shortest-lived piece of the stack. Most systems overwrite on a loop measured in days, not months. A preservation letter that arrives after the loop has come back around is a letter about a clip that no longer exists. The demand should name the camera vendor when it is known and ask for a copy with the metadata intact, not a phone video of a playback screen.
Records A Crash Case Needs
Every system that exists to make a truck safer also creates a record when the truck is not. Trucking evidence collection on a serious crash now reaches across the stack:
Engine event data
The crash snapshot from the module, including the black box download itself.
ELD records
Duty status for at least the seven days before the crash, plus the edit log.
Telematics and alerts
GPS, speed, harsh-braking history, and any safety alerts the carrier already had on this driver.
Camera footage
Forward-facing and in-cab video, with timestamps, before the overwrite loop runs.
Maintenance and inspection files
The paper and electronic repair history that shows whether the truck belonged in service.
When a carrier ignores safety alerts, lets an ELD-documented hours violation stand, or fails to keep the systems that are supposed to prevent crashes in working order, that failure is in the file. The work is finding the file while it still exists, which is why Kentucky truck accident cases move on preservation first and on numbers later. Other episodes in the Truck Talk series pick up the pieces this page only names.
Commercial Truck Litigation Counsel
Handling catastrophic commercial truck collisions requires thorough knowledge of the Federal Motor Carrier Safety Regulations, digital evidence preservation requirements, and corporate motor carrier discovery practices. Jon Hollan and Sam Aguiar maintain selection in the Trucking Trial Lawyers Association Top 10, directing complex commercial vehicle investigations against national transportation carriers.
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