ELDs

Electronic Logging Devices (ELDs) are digital systems that automatically record a commercial driver's Hours of Service (HOS) data by connecting to a vehicle's engine. They replace paper logs and older onboard recorders to improve accuracy, reduce administrative burden, and support safer scheduling and enforcement of driving time rules.

In the United States, the Federal Motor Carrier Safety Administration (FMCSA) regulates ELD use under 49 CFR Part 395 Subpart B. The rule requires most drivers who must log HOS to use an approved ELD, with data transmitted to enforcement or employers and retained for a specified period. Certain short-haul operations within 100 air miles of the driver's normal work location may use non-ELD or paper logs under exemption rules.

ELDs collect data automatically when connected to the vehicle's engine, recording driving status changes (off duty, on duty, driving, sleeper), time, and location. The devices typically store logs locally and transmit them electronically through wireless or USB means. The record is designed to be non-editable by the driver, and carriers must retain ELD data for the required retention period.

ELDs come as built-in vehicle systems or aftermarket devices that are certified or registered with FMCSA. They are intended to improve data integrity and facilitate inspections, but technical issues such as connectivity, device failure, or improper use can affect accuracy. The FMCSA maintains a list of registered ELDs for compliance verification.