Final answer:
A notice downgrading a motor carrier's safety rating from the federal government takes effect immediately upon receipt of the notice.
Step-by-step explanation:
If the federal government sends a notice downgrading a motor carrier's safety rating, the notice takes effect immediately. This immediate effect means that as soon as the motor carrier receives the notice, the new safety rating is in force. While there is typically a process available for appeal, the downgrade is effective right away and does not await the completion of any such appeal process.