According to Title 49 § 395.8, if a motor carrier, "installs and requires a driver to use an AOBRD... before December 18, 2017 they may continue to use the AOBRD until December 16, 2019. If your operation uses AOBRDs before December 18, 2017, and you *replace vehicles in your fleet you can install an AOBRD that was used in the previous CMV. However, you may not purchase and install a new AOBRD in a vehicle after December 18, 2017.
Visit the FMCSA ELD FAQ page for more answers to ELD questions.