During the period when both “grandfathered” AOBRDs and ELDs will be used (December 18, 2017 to December 16, 2019), authorized safety officials will enforce ELD rule requirements for ELDs and the requirements in 49 CFR 395.15 for “grandfathered” AOBRDs. The supporting document requirements for drivers and motor carriers using either device will take effect on the ELD rule compliance date of December 18, 2017.