AOBRD vs ELD – Do You Know The Differences?

Automatic On-Board Recording Devices (AOBRDs) and Electronic Logging Devices (ELDs) are both technologies that help track and manage commercial fleets. But do you know how these recording devices are similar and how they are different? The recent mandate for ELD compliance makes it even more important for fleet companies and drivers to know the differences.

To begin, it helps to review basic definitions of the two terms. AOBRDs refer to electronic or mechanical devices that record driver status information — including engine use, driving speed and distance traveled, as well as the date and time of day. Electronic Logging Devices, known as ELDs, must meet specific requirements from the FMCSA and monitor the engine to track its use, vehicle movement, miles driven and engine hours.

Beyond these basic definitions, it will be helpful to more fully understand the detailed requirements for each type of device:


  1. Recording Requirements: Both AOBRDs and ELDs must capture basic driver duty information. This includes date and time, engine hours, miles, drive times, locations, and duty status. Location information must be recorded at each change-of-duty status.
  2. Tamper Prevention: In either case, the devices should be tamper-proof, though for AOBRDs, the requirement is not specified.


  1. Recording Requirements: In addition to basic information that both require, ELD-compliant technology must also record information that identifies the driver, the motor carrier and the specific vehicle, as well as logins, engine use changes and any malfunctions. Location information must be automatically recorded at change-of-duty status and engine on/off changes.
  2. Integral Synchronization: Although integral synchronization is technically required for AOBRDs, it was not well defined. For the ELD rule, integral synchronization must interface with the engine control module for automatic capture of engine status and hours, vehicle motion and miles.
  3. Tamper Prevention: ELDs cannot permit any changes or deletions of collected data or alterations of the data streams that source the information for the records.
  4. Transferring duty record to an officer: In the case of an AOBRD, the duty record is delivered in either display or print out format as a list of duty changes. By contrast, ELDs must transfer the record electronically to the safety official through wireless web and email or through USB and Bluetooth. The record also must include header information and a grid graph, as well as the duty data list.
  5. Special driving categories: While not addressed for AOBRDs, regulations for ELDs define special driving categories for both yard moves and authorized personal use. These must be manually selected by the driver and may or may not be used by carriers.

The main differences between AOBRDs and ELDs are in the amount and detail of information that must be recorded and in the specifications of recording features. Where AOBRD requirements were vague, the new ELD rule provides much more detail and restrictions on what will qualify.

For fleets and fleet companies, it will be important to keep these similarities and differences in mind when transitioning existing AOBRDs to ELDs. If you would like to learn how to ensure a smooth and effective transition, tune in for next week’s post Transitioning Your Fleet from AOBRDs to ELDs’.

Learn about BSM’s FMCSA compliant ELD solutions, contact us:

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