Trucker question ...tire related

as i go near the interstate every once in a while i cant help but notice something that is kinda strange to me.

Truckers can shed light on this:

why do some trucks have a double wide tire and not the dually setup like others?

i think its a new idea....and it seems to have advantages and disavantages.

these double wide tires seem to make more noise.

are there any real advantages to them over the classic dually set up and is this something that will be standard in the future?