What Is an ELD? A Plain-English Explainer

What an ELD records

An ELD is a device and software pair that records a driver's duty status automatically. The device plugs into the engine's diagnostic port and knows when the truck moves. Under 49 CFR 395.26, the ELD records these data elements:

• Date
• Time
• Vehicle location
• Engine hours
• Vehicle miles
• Driver or authenticated user identification
• Vehicle identification
• Motor carrier identification

It captures that full set at every change of duty status, when the engine powers up or shuts down, and when a driver logs in or out. While the truck is moving with no status change, the ELD adds an intermediate record at least once an hour. During authorized personal use, location is recorded at a coarse resolution, roughly within 10 miles.

The driver still chooses some statuses by hand, like off duty, sleeper berth, and on duty not driving. Driving time is the part the driver cannot type in. When the truck moves, the clock runs.

Who must use an ELD

Under 49 CFR 395.8, a motor carrier operating commercial motor vehicles must have its drivers record duty status on an ELD. A few groups may use paper logs instead, including drivers who keep logs on no more than 8 days in any 30-day period, certain driveaway-towaway operations, and vehicles built before model year 2000. Short-haul drivers who qualify for the logbook exception keep time records instead of logs.

Whether you count as a commercial motor vehicle depends on weight, passengers, hazmat, and interstate operation. The ELD mandate guide walks through who is covered, and ELD exemptions covers the exceptions in detail.

From paper logs to AOBRDs to ELDs

For decades, drivers kept paper logs on a 24-hour graph grid. Some carriers adopted automatic on-board recording devices (AOBRDs), an older electronic standard with looser technical rules.

The ELD rule set December 18, 2017 as the date carriers had to use ELDs. Carriers that had installed AOBRDs before that date could keep using them until December 16, 2019, under the old 49 CFR 395.15. Since then, AOBRDs are no longer accepted, and every carrier subject to the rule must use a registered ELD.

Hardware, app, or both

A registered ELD is a system. It usually has three pieces:

• The device that connects to the engine and reads engine hours, miles, and motion.
• The driver app on a phone or tablet, where the driver changes status, certifies logs, and shows records to an officer.
• The back office, a web portal and cloud service where the carrier reviews logs and keeps records.

An app on its own, with no engine connection, cannot meet the rule's requirement to record engine data. That is why ELD providers ship a plug-in device.

Devices also differ in how they get location. A Bluetooth-only device like the Pacific Track PT-30 uses the driver's phone for GPS. The PT-40 has its own GPS and LTE connection, so the truck keeps reporting even when the phone is dead or left at home. See PT-30 vs PT-40 for the details.

What else an ELD does

Beyond the log itself, most ELD systems handle the paperwork around it. DocuDrive includes driver vehicle inspection reports (DVIR), IFTA mileage by jurisdiction, real-time GPS tracking, and a roadside Inspection Mode, all in $20 per truck per month.

At a roadside inspection, the driver either shows the log on screen or transfers it to the officer. DocuDrive transfers logs telematically, by web services and email, from the app's Inspection Mode. The DOT inspection guide covers what officers ask for.

When an ELD malfunctions

ELDs fail now and then: a loose cable, a dead tablet, a device that will not connect. The rules in 49 CFR 395.34 set out what happens next. The driver notes the malfunction and gives the carrier written notice within 24 hours, reconstructs the current day and previous 7 days on paper unless the records can be pulled from the ELD, and keeps paper logs until the ELD is fixed. The carrier then has 8 days from discovery to repair or replace it. That is why every cab carries a supply of blank paper grids.

How to check that an ELD is registered

ELD makers self-certify their devices and register them with FMCSA, and carriers must use a registered ELD (49 CFR 395.22). FMCSA keeps the public list at eld.fmcsa.dot.gov. Search for the product and confirm the name, model, and ELD identifier match what you were sold. Also check the revoked list. A carrier using a revoked device has a limited window to replace it.

DocuDrive Logbook is registered as model DOC-5, ELD identifier DDL996, by DocuDrive LLC. More on what registration means on the FMCSA-registered ELD page.