>I bet it's not pronounced the same. Is it ar-TIC, just like ar-TIC-ulated? (As opposed to AR-tic.)

No AR-tic or quite often, just to confuse people - ARC-tic. I'd always wondered if people were thinking it was to do with the arctic or just adding an extra consonant because it sounds better (you know how we like those extra letters).

Never heard of semi- or whatever trailer but maybe that is what they are called technically. I don't think that our roads are straight enough for more than two linked together. Sometimes you see really huge things on the motorway with accompanying police motor bikes to warn people, especially if it is an extra wide or slow load.