Post Office Tracking Scan Code. 59 ON ROUTE A physical scan event stating that the article has left the delivery office with a carrier and delivery is intended on that day. Global Express Guaranteed.

And here is a screenshot of the locations page on the USPS website. Button that appears on your iPhone keyboard. Whenever you post a package the post office workers assign a number to that order that number is called USPS Tracking Number.
Track your items just enter your tracking ID number or scan the barcode to check the progress of your deliveries available with Royal Mail Tracked and Royal Mail Special Delivery Guaranteed items.
Below is a picture of the QR Code that is on the front door of the post office. POSTNET barcodes on US. It is also known as label or article number. This is a great use of a QR Code in my opinion.