Exploring jamming transitions and density waves in bidirectional pedestrian traffic Y. Xue, H.-H. Tian, H.-D. He, W.-Z. Lu and Y.-F. Wei Eur. Phys. J. B, 69 2 (2009) 289-295 Published online: 05 May 2009 DOI: 10.1140/epjb/e2009-00149-8