The Netherlands have a tradition of high bicycle usage and a long history of research on effective policies for promoting cycling. Findings in Dutch studies can be useful in the Danish Bikeability-project that has the objective to increase the level of knowledge in relation to bicycle based transport and to contribute to more efficient and qualified urban planning and management. This report discusses a number of Dutch case studies on the effects of investments in bicycle infrastructure. The reviewed studies include the three ‘classical’ cases in the 20th century: rather large investments in the cities of Tilburg, The Hague and Delft that were evaluated extensively by before and after studies. Other, smaller and more recent cases include the evaluation of shared space, a bicycle street, and interurban highways for cyclists. A general conclusion is that policies can be effective in sustaining high levels of cycling and strengthening cycling culture.