A local authority can specify densities for new development. Higher densities enable more opportunities to be reached within a given distance, and hence may encourage shorter journeys and use of cycling and walking. By increasing population and employment densities, they may also make public transport more viable. However, there is very little evidence of the scale of these effects, except for cross-sectional comparisons which demonstrate that residents in lower density areas are more likely to use the car and to travel longer distances. 69 As with other land use measures, increased densities are only likely to be effective if developers respond positively and if users elect in practice to travel to opportunities nearer to towns and workplaces. There is evidence that developers are prepared to accept denser development, not least because it increases the return on land investment, but there is little evidence on the response of users.