Words fail me...

Tri axles with single tires usually run Europe

 

Trailer tires, width of trailer frame, and you can see the front corner of a Euro-style cabover.

 

My guess is someone is stealing gasoline or diesel from surrounding vehicles, stashing the bottles in a parked trailer and will return to "fill up" that night.
It is labor intensive, but you can shove one of those bottles down a filler with a stick and a string tied to it.

 

also I don't recognize any of the name brands or even colors of presumably soda pop that the containers were originally used.

 

And the reason I think it’s fuel of some type is because nobody going to have gallons of urine that is the exact same color.

 

They better work quick If it’s gas it won’t be long before it eats through those bottles.

 

Not U.S. Look at the front of that bike. That's in Asia or Europe somewhere guaranteed. Where around here are little motorcycles parked around big trucks?

That ain't piss either. No one is that crazy. It's gotta be fuel or something illegal.

 

Looks like the person called to fix the tire is the source of this picture.