Street Parking Near Mailboxes

If we park a vehicle on the street during the daytime we all know to leave space so the mail truck can reach the mailbox. What we don’t know is we must also leave space for the mail truck to pull straight away from the mailbox. USPS rules do not allow vehicles to back up except in the most extreme circumstances. Please leave enough space for the mail truck to pull up to and away from the mailbox. Thanks.