“…population density (Hadayeghi et al, 2003;Noland and Quddus, 2004;Huang et al, 2010;Tolón-Becerra et al, 2012;Lee et al, 2014b), age groups (Noland, 2003;Noland and Oh, 2004;Noland and Quddus, 2004;Aguero-Valverde and Jovanis, 2006;Quddus, 2008;Huang et al, 2010;Aguero-Valverde, 2013;Lee et al, 2014a), income (Noland, 2003;Traynor, 2008;Pirdavani et al, 2012), GDPs (Kumara and Chin, 2004;Tolón-Becerra et al, 2012), and employment (Siddiqui et al, 2012); land use variables Lovegrove and Sayed, 2006;Pulugurtha et al, 2013;Wang et al, 2013;Lee et al, 2014b); healthcare variables Coruh et al, 2015); road infrastructure variables, e.g. road density, intersection density, road length (Amoros et al, 2003;Hadayeghi et al, 2003;Noland, 2003;Lovegrove and Sayed, 2006;Pirdavani et al, 2012;Tolón-Becerra et al, 2012;Jiang et al, 2016), roads with different functions (Lovegrove and Sayed, 2006;Huang et al, 2010), and road network structures Moeinaddini et al, 2014); traffic pattern variables, e.g. vehicle kilometres travelled (VKT) (Dumbaugh and Rae, 2009;Abdel-Aty et al, 2013;AgueroValverde, 2013), highway usage …”