Geographical Information System (GIS) software is frequently used to provide spatial information, but at present no commercial GIS allows a dimension of decision-making to be integrated with this. Software has now been produced that includes a group decision support system (DSS), and this looks set to play a key role in the future development of urban planning strategies. The user can input a range of details specific to the project, and the software then assesses the impact of policies from various perspectives. The software allows a range of conflicting issues to be assessed and prioritised. The resulting decision support system can then be used to design sustainable transport policies that minimise conflict. The new software is extremely versatile, and can be used over a range of spatial scales. It enables the impact of a strategy to be seen in terms of effects on the local region, and also at the national scale.