Scientific Reports 3, Article number: 2153 (2013); Published: 8 July 2013; Updated: 12 November 2013

There are referencing errors in the HTML version of this Article. All citations of reference ‘21’ should be to ‘22’, ‘22’ to ‘23’, ‘23’ to ‘24’, ‘24’ to ‘25’, ‘25’ to ‘26’, ‘26’ to ‘27’, ‘27’ to ‘28’ and ‘28’ to ‘29’. In addition, reference 21 should be included in the citations at the end of the first paragraph of the Introduction. The final sentence of the first paragraph of the Introduction should read: “These network aspects were first studied in the 1960s in quantitative geography13 and in the last decade, complex networks theory has provided significant contributions to the quantitative characterization of urban street patterns14–24”. The PDF version of the Article is correct.