This is the road transportation network of the Chicago region (USA). Nodes are transport nodes, and edges are connections.
Data downloaded from http://konect.uni-koblenz.de/ orginaly from http://www.bgu.ac.il/~bargera/tntp/
Jerome Kunegis. KONECT - The Koblenz Network Collection. In Proc. Int. Web Observatory Workshop, pages 1343-1350, 2013.
R. W. Eash, K. S. Chon, Y. J. Lee, and D. E. Boyce. Equilibrium traffic assignment on an aggregated highway network for sketch planning. Transportation Research Record, 994:30--37, 1983.