You see a lane marked out with solid and broken yellow lines. What is this lane for?

This is a shared center lane. This lane is designed for left turns only. Traffic moving in either direction can use this lane to turn left. This lane is not for passing or general driving. [Pavement Markings Indicating Turn Lanes, Pavement Markings, Chapter 4: Traffic Signs, Signals and Road Markings, Utah Driver Handbook]