The ELD mandate, which became fully effective for most commercial drivers in December 2019, replaced the paper log books that had been the primary Hours of Service recording method for decades. ELDs automatically capture driving time when the commercial motor vehicle is in motion, eliminating the ability to manually adjust hours or backfill records.
ELDs connect to the vehicle's engine to record engine-on and engine-off events, vehicle motion, and GPS location. The device updates the driver's electronic log in real time. When a driver switches between duty statuses (off duty, sleeper berth, on duty not driving, driving), they update their status on the ELD interface.
For carriers, ELDs provide real-time fleet visibility. A dispatcher can see where every driver is, how many hours they have remaining in their shift, and whether they are on time for their next appointment. This visibility improves planning accuracy and reduces late calls when drivers are running out of available hours.
For shippers, ELD enforcement has a direct impact on transit reliability. Pre-ELD, drivers could informally push beyond their legal limits, creating informal transit speed that wasn't sustainable or legally compliant. Post-ELD, transit estimates need to reflect legal service windows. A shipper who expects a 600-mile delivery to be completed in 10 hours is expecting the driver to violate HOS regulations — that freight will arrive in two days, not one.
ELD exemptions exist for short-haul drivers operating within 150 air miles of their home terminal, certain agricultural operations, and a small number of other categories. Most over-the-road dry van drivers are subject to full ELD requirements.