This is a question for any linemen out there...
How do you get a set of lines across a major interstate freeway? I assume you divert traffic for a while to run a messenger, but what if there is no frontage to divert traffic to? I saw a couple of what looked like 7.2KV 3 phase wye sets run across I-15 and one was where there is nothing but the freeway. Just curious...

Helicoper is one way.

You pretty rarely get to shut anything down. The way it's normally done in a busy environment is for a relay of bucket trucks, one on each side of the highway and one in the middle (sometimes you need more, sometimes less).

One bucket has the cable, passes it off to the next and stays there feeding it across, and so on until you have it across and the span is properly "slacked".

Not really complicated, ya just GOTTA remember to have your boom above the 18' level.....or else.

I have seen it done here in Manitoba where they close off the highway between 11 pm and 5 am to do it.

The last one I remember seeing done took two nights. The first night to get all the lines across and the second night to get the sag set. The contractor set some temporary poles with crossarms in the middle of the median to keep the conductors from falling onto the asphalt as they were pulling them.

Never thought about the set of bucket trucks. That wouldn't be bad for a couple of lanes, but a different story for Salt lake where there are 6 lanes... But you could funnel it down to two lanes on graveyard shift.
Sure beats sending the apprentice across the freeway with a messenger tied to his belt...

Would you believe me, if I said we save all such work for September, and the National Baloon Races? :-)

Umm, no.