They've been building the Fourth Ring Road on and off. According to its project, after they open the Forth Ring Road, the traffic jam situation on the MKAD and the Third Ring Road will improve.
The work began in 2008 with the construction of a parking lot which was to be above the road. Apparently, the builders were very enthusiastic about it at first, so the pace of construction was really fast.
In the end of 2009, they opened 4 auxiliary traffic lanes... and that's it.