First, we know the reason a bike will continue on its path isn't just because of the force of momentum pushing it there. We know that because if you lock a bicycle's handlebars so that they can't turn, then the bike falls over, regardless of how fast it's moving. So part of this riderless bike phenomenon has to do with its self-steering properties.
Thanks, I didn't make it that far into the article before giving up on it. It's still a weirdly sensational article, and the video I linked mentions that bikes are specifically engineered. The principles for why a bike stays up are well known and not a mystery of science.