Citizen commissions are in place in six states: Arkansas, Arizona, California, Idaho, Montana, and Washington.
California is the closest analogy to what we’re trying to do in Pennsylvania with SB 22 and the original HB 722. The California Citizens Redistricting Commission was established to draw state legislative districts with the passage of Proposition 11 in 2008, and was authorized to draw congressional districts with the passage of Proposition 20 in 2010.
The difference is that California got the issue onto the popular ballot without going through the legislature, due to their more accessible system for public ballot propositions. To adopt a citizens commission in Pennsylvania, where the state constitution defines the redistricting process, a bill to amend the constitution has to pass in two successive sessions of the General Assembly. Only then can the proposed amendment be brought up for a popular vote.