Twin Cities commuters rode the Green Line's stretch of rail between the downtowns of Minneapolis and St. Paul about 5.6 million times between January and May, according to Metro Transit data, 12 percent more than the Blue Line's 5 million ridership over the same period.

Since the Green Line opened in June 2014, it has seen an average of more than 30,000 riders boarding its trains each day. About 22 percent of riders this year boarded at stops along the University of Minnesota while about 21 percent boarded from downtown St. Paul stations.