USPS Tracking provides proof of delivery to sorting facilities, local post office and destination, but no signature is required.
The United States Postal Service, also known as the Post Office, U.S. Mail, or Postal Service, often abbreviated as USPS, is an independent agency of the United States government responsible for providing postal service in the United States. It is one of the few government agencies explicitly authorized by the United States Constitution.
The USPS as of February 2015 has 617,254 active employees and operated 211,264 vehicles in 2014. The USPS is the operator of the largest civilian vehicle fleet in the world. The USPS is legally obligated to serve all Americans, regardless of geography, at uniform price and quality. The USPS has exclusive access to letter boxes marked "U.S. Mail" and personal letterboxes in the United States, but still competes against private package delivery services, such as the United Parcel Service (UPS) and has part use with FedEx Express.