Graphs adjacency vectors - files

Question

I need some graphs represented as adjacency vectors. The number of vertexes can achieve some tens of thousands (eg 20.000-50.000). Don't know if it matters, I am using C code.

Do you know any site where I can retrieve such data files?

Answer 1

A very praxis relevant graph is a digital road map. (As used in navigation systems) OpenStreetMap provides these vectors. But you have to build up yourself the adjacencies.