This discussion paper resulted in a publication in <A HREF="http://www.sciencedirect.com/science/article/pii/S019126151300043X">'Transportation Research Part B: Methodological'</A>, 2013, 53, 31-44. We analyse the behaviour of market participants in a multi-modal commuter network where roads are not priced, but public transport has a usage fee, which is set while taking the...</a>