While there is a myriad policies that shape the urban form, this section takes a closer look at policy tools related to housing, transport and environmental policies. Access to housing is precisely reported as one of the five most important objectives of housing policy by all 26 OECD countries that took the recent Questionnaire on Affordable and Social Housing (QuASH) (OECD, 2014d), including 18 countries that explicitly mentioned improving the affordability of housing (Salvi del Pero et al., As documented in Chapter 2, people living in large cities are, on average, less satisfied than the national average (by 13.3 percentage points) with the affordability of housing. For example, national fiscal frameworks may make greenfield development more attractive to cities than infill development.