The Maryland Motor Truck Association recently alerted its members that UCR registrations have been delayed. Even though Maryland is not a Unified Carrier Registration State, most of the surrounding states ARE, which would necessitate anyway driving through those states to register and pay the fees.
However, the FMCSA has not finalized all the policy making rules for this law, and USR Board of Directors has asked states to hold off on taking registrations or enforcement of the law until all particulars are worked out.
For more information, please see this article.