Do I need UCR if I operate in only one state?
Only if you operate interstate (cross state lines for any portion of any trip). Pure intrastate carriers operating exclusively within one state do not need UCR. The trigger is interstate commerce, not the breadth of operations — even occasional interstate trips bring the carrier into UCR scope.
UCR under 49 CFR Part 367 applies to interstate operations. If the carrier crosses state lines for any portion of any trip during the year, they are an interstate carrier and need UCR. The frequency or volume of interstate operations does not change the requirement — one interstate load makes the carrier interstate.
Pure intrastate carriers — those who operate exclusively within one state, never cross state lines — are not subject to UCR. They typically register under state-level intrastate authority instead (CA intrastate carrier permit, NY intrastate authority, etc.).
A common boundary case: a carrier whose home state is interstate (they have interstate authority) but whose actual operations are 99% intrastate. They still need UCR because they hold interstate authority. The threshold is having the authority, not exercising it.
Carriers transitioning from intrastate to interstate during the year typically file UCR at the start of the calendar year following the transition, or immediately if mid-year operations include interstate trips.