FMCSA - Federal Motor Carrier Safety Adminstration
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About ELDs

Improving Safety Through Technology

Electronic logging devices ensure that all drivers of commercial motor vehicles get the rest they need to drive safely.

How Does an ELD Work?

An ELD synchronizes with a vehicle’s engine to automatically record a driver’s off-duty and on-duty time and securely transfer HOS data to a safety official.


The ELD synchronizes with the CMV engine to automatically record:

  • Engine power status
  • Vehicle motion status
  • Miles driven
  • Engine hours
  • Identification of driver/authorized user, vehicle, and motor carrier
  • Duty status


The driver uses the ELD to certify that his or her record of duty status (RODS) is complete and accurate.

The ELD will allow the driver to enter annotations to offer further detail on any of the recorded events or driving time. The motor carrier can suggest edits to non-driving time, which are either accepted or rejected by the driver during RODS certification.


Upon request, the driver initiates data transfer. Data is routed to the safety official using secure methods.

Option 1

Both ELD and safety official must connect to internet

Web Services

Option 2

No internet connection required for driver or motor carrier

USB 2.0
Bluetooth ®


The safety official opens the Electronic Record of Duty Status (eRODS) software and uses it to locate, open, and review the ELD file. eRODS identifies potential hours-of-service (HOS) violations for the safety official to review and, when appropriate, cite.

When necessary, safety officials can also review HOS data using the backup method supported by the ELD—either the on-screen display or a printout.

About the ELD Rule

The ELD Rule:

  • Lists who is subject to the ELD rule and exceptions to it.
  • Explains FMCSA’s self-certification and registration process.
  • Details all technical specifications of a compliant ELD.
  • Outlines a phased implementation timeline to give motor carriers time to comply.
  • Includes provisions to help prevent data tampering and harassment of drivers.
  • Creates standard data displays and data transfer processes, making it easier to demonstrate compliance and faster to share RODS with safety officials.
Read the ELD Rule