Conclusions
The Walkability PSS could be further developed to include other health and environmental outcomes as well as other built environment variables. For example, future PSS research could incorporate urban sustainability analyses and models (Chen and Crawford, 2015) into customised formulae. This would enable the environmental co-benefits of urban design interventions to be presented using interactive indicators within a PSS i.e., levels of greenhouse gas emission associated with planning scenarios as is included in another PSS such as the Envision Scenario Planner (ESP) tool (Trubka et al., 2016). As the complexity of developing PSSs increases, there is potential for PSSs to be abstracted from urban planners hindering their adoption for planning purposes (Waddell, 2011). Waddell (2011) explains that transparency matters for building trust and facilitating adoption since “models will not have credibility as tools for decision support in complex, conflictladen domains such as land use, transportation and environmental planning, unless they can be explained with a sufficient degree of transparency” (Waddell, 2011). Yet an over-simplification of models within PSSs also poses a problem as it reduces precision, validity and eventually credibility (Waddell, 2011). Hence, it is recommended that future research examines the trade-off of model complexity, transparency and PSS interactivity and further usability test be undertaken of the Walkability PSS tool to understand and address potential barriers of adoption by planning professionals.
