The table below compares the technical specifications in the AOBRD rule (49 CFR 395.15) and the ELD rule.
| Feature/Function | 1988 AOBRD Rule | ELD Rule |
| Integral Synchronization | Integral synchronization required, but term not defined in the Federal Motor Carrier Safety Regulations (FMCSRs). | Integral synchronization interfacing with the CMV engine electronic control module (ECM), to automatically capture engine power status, vehicle motion status, miles driven, engine hours. (CMVs older than model year 2000 exempted.) |
| Recording Location Information of Commercial Motor Vehicle (CMV) | Required at each change of duty status. Manual or automated. | Requires automated entry at each change of duty status, at 60-minute intervals while CMV is in motion, at engine-on and engine-off instances, and at beginning and end of personal use and yard moves. |
| Graph Grid Display | Not required – “time and sequence of duty status changes.” | An ELD must be able to present a graph grid of driver’s daily duty status changes either on a display or on a printout. |
| Hours of Service (HOS) Driver Advisory Messages | Not addressed. | HOS limits notification is not required. “Unassigned driving time/miles” warning must be provided upon login. |
| Device “Default” Duty Status | Not addressed. | On-duty not driving status, when CMV has not been in-motion for five consecutive minutes, and driver has not responded to an ELD prompt within one minute. No other non-driver-initiated status change is allowed. |
| Clock Time Drift | Not addressed. | ELD time must be synchronized to Universal Coordinated Time (UTC); absolute deviation must not exceed 10 minutes at any time. |
| Feature/Function | 1988 AOBRD Rule | ELD Rule |
| Communications Methods | Integral synchronization required, but term not defined in the Federal Motor Carrier Safety Regulations (FMCSRs). | Integral synchronization interfacing with the CMV engine electronic control module (ECM), to automatically capture engine power status, vehicle motion status, miles driven, engine hours. (CMVs older than model year 2000 exempted.) |
| Resistance to Tampering | Required at each change of duty status. Manual or automated. | Requires automated entry at each change of duty status, at 60-minute intervals while CMV is in motion, at engine-on and engine-off instances, and at beginning and end of personal use and yard moves. |
| Graph Grid Display | Not required – “time and sequence of duty status changes.” | An ELD must be able to present a graph grid of driver’s daily duty status changes either on a display or on a printout. |
