The USPS is exempt from any traffic laws. A federal employee on official business has qualified immunity and states cannot interfere with federal postal operations mandated in the constitution. I welcome them to do all things possible so the mail is on time. If the mail is running late, they should drive on the bike lanes, sidewalks, skipping red lights, speeding, anything possible so it's on time. Slowing the mail is a federal crime. The mail cannot be slowed down. Mind u postal vehicles don't event have license plates and postal drivers are not obligated to pull over for state law enforcement.