What were the enforcement procedures for “grandfathered” AOBRDs and ELDs during the two-year period following the compliance date of the ELD rule?

During the period when both �grandfathered� AOBRDs and ELDs were allowed (December 18, 2017 to December 16, 2019), authorized safety officials enforced 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 applied on and after the ELD rule compliance date of December 18, 2017.