During each run junctions will appear intermittently, they will be signposted by the big arrows at the side of the track and taking one will have several benefits. Junctions will enable you to 'bank' any rings you currently hold so that you are guaranteed they will be added to your total at the end of the run and you will have a bonus added to your total that accumulates with each additional junction you take. Junctions will also allow you to change characters mid-run allowing you to use each characters special power accordingly.