Why are 18-wheelers called "semi's"?

[QUOTE=Krokodil]
What is the greatest number of trailers a tractor will pull? Out west, I see as many as three, but around here, just one.
[/QUOTE]

112

On a typical road train, I think it’s more like three or four.

[QUOTE=CookingWithGas]
American English hates a long phrase if a short phrase works just as well.
[/QUOTE]
And so does just about every other language.

Long words are less frequently used than short words, in natural languages. Longer words or multi-word phrases, as they begin to be used more frequently, become shorter.

Thus television receiver set becomes television becomes TV.

In the science of linguistics, this is known as Zipf’s Law.

[QUOTE=dbuzman]
No, Cab-over Pete had a reefer on (was pulling a refrigerated trailer).
[/QUOTE]
Remember that the truck names in the song referred to the trucks themselves–“Cab-over Pete” was a cab-over Peterbilt. The song also mentions “a Jimmy hauling hogs,” which would be a GMC truck.

As for fuel capacity, I seem to recall that 900 liters (about 238 gallons) was a typical full tank back when I did some driving. At least it was on the trucks I drove (I didn’t drive reefers).