As far as fault goes, it could depend on multiple factors, but it is based on the state codes in that I'll cite below. As far as citations go, it's also based on the codes below, and would depend exactly on the place of the collision.

If you are wanting to use that center lane to turn left, vehicles by law cannot enter that lane more than 500 feet prior to making the turn - and yes, in Utah, people will hop over in that lane and drive 1/4 mile to bypass stopped or crawling traffic in the main lanes, and it is illegal to do so - they must stay in a normal lanes of travel (not the center multipurpose lane) until within 500 feet of the turn, unless traffic to turn is stacked up 500 feet or more, in which case they can enter immediately behind the last car in line. So, if the car hops in more than 500 feet prior and collides with a vehicle, they could be cited on this statute. This is based on UT code 41-6a-801, subsection (3)(c):

http://www.le.utah.gov/xcode/Title41/Chapter6A/41-6a-S801.html?v=C41-6a-S801_2015051220150512

As far as a vehicle pulling in from a side street, they cannot pull directly from the side street into the center multipurpose/turn lane if they are turning right. They must enter into the nearest lane if it is a right turn, and make proper lane changes over to the center/multipurpose lane, and if they are making a left turn, they must yield to existing traffic already in that multipurpose lane before making that turn off a side street into the larger street, if they are using the multipurpose lane prior to merging. Most of this is governed by the lane marking statute, 41-6a-710, but also in other statutes involving yielding to other vehicles.

http://www.le.utah.gov/xcode/Title41/Chapter6A/41-6a-S710.html?v=C41-6a-S710_2015051220150512

Any citation would be issued upon probably cause of a violation of one of these statutes, fault would be determined by insurance companies.

I hope I understood that right, and I hope that helps!