This article is by the UK-based "Transport & Environment". That is mentioned right in the article.There is nothing in this article about the USPS.
Also, there is nothing about refueling infrastructure.
This article is about Thermal Efficiency, and calculating the "wheels to well" thermal efficiency of the various systems to drive a vehicle.
The first paragraph lays out the premise, that " If you want to drive the absolute cleanest car possible – and if you’re reading this site, we’re willing to wager that you do – then you need to calculate the total well-to-wheels energy use of the car and everything you put into its tank or battery."
Why do you see some extrapolation here to the American Postal Service?
Thanks!
:-)
JMI