What Is an ELD? Electronic Logging Devices Explained

What an ELD actually does

An ELD is two parts working together: a small device plugged into the truck's diagnostic port, and an app the driver signs into. The device reads the engine control module directly, so it knows when the truck is moving without the driver touching anything. The app turns that data into a compliant record of duty status.

• Records driving time automatically the moment the truck moves above about 5 mph
• Captures engine hours, odometer miles, and GPS location at each duty-status change
• Lets the driver annotate, certify, and edit non-driving time (driving time cannot be erased)
• Transfers the last 8 days of logs to a DOT officer by email, web services, Bluetooth, or USB
• Warns the driver before an 11-hour or 14-hour limit is broken

ELD vs AOBRD vs paper logs

Paper logs were replaced by AOBRDs (automatic on-board recording devices), and AOBRDs were fully phased out on December 16, 2019. Only FMCSA-registered ELDs are legal for drivers who are required to keep records of duty status. The practical difference is tamper resistance: an ELD locks driving time, forces an audit trail on every edit, and standardizes the roadside data transfer format.

Who has to use an ELD

The rule applies to most drivers who are required to keep records of duty status under 49 CFR Part 395 — generally commercial motor vehicles over 10,001 lbs, or those carrying placarded hazmat or 9+ passengers, operating in interstate commerce. There are narrow exemptions, including trucks with a pre-2000 engine, short-haul drivers who stay within the 150 air-mile radius and return to base within 14 hours, and driveaway-towaway operations.

What ELD hardware looks like

Most small-fleet ELDs use a plug-in OBD-II or 9-pin device about the size of a deck of cards. The two devices that dominate the small-fleet market are the PT-30 (Pacific Track) and IOSiX units — both are provider-configurable, which is why you can usually keep the hardware when you change ELD companies. Installation takes under ten minutes and does not require a mechanic.

• Light and medium-duty trucks: OBD-II port under the dash
• Heavy-duty trucks: 9-pin or 6-pin Deutsch connector
• Bluetooth pairs the device with the driver's phone or tablet
• ELD Hub sells the PT-30 at $150 with cable and free ground shipping, and re-registers PT-30 or IOSiX devices you already own at no cost

What an ELD costs in 2026

Across the 15 providers in our market report, software runs $15 to $45 per truck per month and hardware runs $100 to $250 per device. Three-year total cost of ownership ranges from about $690 to $1,820 per truck. The biggest cost driver is not the device — it is contract length and paid add-ons like IFTA reporting, which some providers bill separately even though the ELD already collects the mileage data.

How to choose an ELD for a small fleet

For an owner-operator or a fleet under 20 trucks, the deciding factors are almost never advanced telematics. They are price, contract terms, whether IFTA and DVIRs are included, how fast a human answers the phone during a roadside inspection, and whether the device is one you can keep if you leave.

• Confirm the provider is on the official FMCSA registered ELD list
• Ask what happens on cancellation — six of 15 major providers charge 50 to 100% of the remaining contract
• Check whether IFTA fuel-tax reporting is included or billed as an add-on
• Ask whether the hardware is provider-locked or re-registerable
• Test the support line before you sign, not during an inspection