Well, almost nothing to show for it. USPS spent $3B on electric trucks and barely delivered results
The tl:dr version of the story. The USPS spent $3 billion dollars and has 612 electric trucks. That overstates the problem, a bit, because they weren't going for 100% electric vehicles. They also purchased some E-Transit vans from Ford, but quite of few of those are sitting idle around the country.
And of course they couldn't just go an purchase a known vehicle, like the E-Transit, or a Chevy van. No, this is the US government, and so the USPS decided that they needed custom vehicles designed and built by Oshkosh. (A company that makes Fire Engines, but mostly they make trucks for the US military.)
As usual, it comes down to charging. Even in places where EVs might make sense, charging infrastructure is not in place. Another case of where bureaucrats make decisions about engineering with no engineering knowledge. "What could possibly go wrong?"
Even where vehicles exist, the supporting infrastructure has lagged. Internal and external critics have pointed out that the infrastructure for new EV delivery vehicles simply did not exist at many postal facilities, and that older buildings needed to be retrofitted for EV charging before large numbers of trucks could be assigned there.
Your tax dollars at work. (Hat tip to MGUY Australia.)
