[aerohead]

It may be a COPOUT-26 climate gesture. A 'small' gesture, and signal to the rest of the climate community that, the USA will put your money where their mouth is.
By the way, NASA has picked up a recent spike in satellite-monitored carbon-dioxide emissions from Denton, County, Texas.
The new source is rural US Postal Service mail carriers, borrowing a trick the Public School buses use : stopping along 60-mph two-lane arterials, in no-passing zones.
Swarms of 70-mph traffic ( nobody obeys speed limits, and nobody enforces them either ) must come to a complete halt, while the mail trucks deliver.
Texas Department of Public Safety officers are on the ready to issue traffic citations, if anyone attempts to pass the mail carriers.
In other Universes, counties provide alcoves, off the thoroughfare, onto which a school bus or mail carrier could pull onto, without bottling up operating tailpipes, a major contributor to global warming according to the US EPA.
My heart just swells with joy as I witness such brilliant public policy at work! Such a warm, fuzzy feeling.