We are currently working on establishing a common open source license for all EuroVelo tracks. At the moment, there is no clarity on the general EuroVelo license - each track belongs to the National EuroVelo Coordination Centre (NECC) that is managing it, and sometimes tracks belong to the regions that they get them from. This complicates everything because the license then is different in each country.
We are going to make a proposal to the NECC for a common open source license. Do you know which licenses make it easy for OSM? If we go for a license of the type ODC-by, with required attribution of www.EuroVelo.com, would that make things complicated on OSM? I would guess yes, since the required attribution changes when we put tracks on OSM?
Regarding Sustrans, EuroVelo routes should follow the NCN routes and change when the NCN is modified. However, we don’t always receive timely updates from Sustrans and our tracks in the UK are quite bad and imprecise. OSM could maybe help with improving www.EuroVelo.com in this case! If there are doubts, Sustrans is our NECC in the UK and responsible for deciding what NCN routes the EuroVelo itineraries should follow. But most of the routes are not signed with EuroVelo signs in the UK, so easy to modify.