img = WolframAlpha["Champaign IL",{{"Map:CityData",1},"Image"}];
g=MorphologicalGraph[Binarize[ColorNegate[img]],EdgeStyle-> LightGray,VertexStyle->LightGray];
Column[{img,HighlightGraph[g,NeighborhoodGraph[g,125,20],ImageSize->500]}]