Boulder elected its mayor for the first time and also used ranked-choice voting to do so. This was an example of a “come from behind” RCV win. In the initial tally, two candidates from the Boulder Progressives split the vote and another candidate received the plurality of first-place preferences, with 43% of the vote. When one of the Progressive candidates was eliminated and votes redistributed, the other Progressive candidate ended up being elected, with 51% of the vote.

Here’s an editorial from the Boulder Daily Camera on the pros and cons of how the system worked out, which concludes largely favorable to RCV:

“But, generally speaking, ranked choice voting was a success in Boulder. It gave voters real choices, it ensured that our mayor was elected by majority and it prevented the need for a runoff election. “