The European Data Portal shows a growing number of governmental organisations opening uptransport data. As end-users need traffic or transit updates on their day to day travels, route planners need access to this government data to make intelligent decisions. Developers however, will not integrate a dataset when the cost for adoption is too high. In this article, we study the internal and technological challenges to publish data from the Department of Transport and Public Works in Flanders for maximum reuse. Using the qualitative ESTEEM research approach, we interviewed 27 governmental data owners and organised both an internal workshop as a matchmaking workshop. In these workshops, data interoperability was discussed on 4 levels: legal, syntactic, semantic
and querying. The interviews were summarised in 10 challenges to which possible solutions were formulated. The effort needed to reuse existing public datasets today is high, yet we see the first evidence of datasets being reused in a legally and syntactically interoperable way. Publishing data so that it is reusable in an affordable way is still challenging.