THREE
Yes, Mexico imports regular diesel from the USA
By "regular diesel" do you mean LSD or ULSD? It is my understanding based on all I have been able to find and all I have read that since sometime in 2014 no refinery in the USA produces LSD - only ULSD is produced in the USA. But I am just doing research and searching so I have no personal knowledge. What I have read is that part of the law for the US since the changeover began in 2007 says there will be no more ULSD produce in the USA. Is there any information that says otherwise that can be found on any accessible website? All diesel in the USA - whether it be for cars or trucks or boats or locomotives or power plants must now be ULSD. No pipelines or storage tanks or trucks or tankers or whatever can be used for both fuels so transportation and storage is now only for ULSD in the US.
Not being all that knowledgeable about the process (I expect others may not be either) I do not know all this technical coking and cracking and the rest of it. Is there a way to put it all into terms a laymen can understand?