Tools that can be applied to different scales of infrastructure development to support evidenced-based decision-making within infrastructure planning processes. These tools simulate infrastructure systems and their interaction with various social, economic, and environmental systems. They use mathematical formulas and algorithms to show what happens when different variables are introduced, helping planners to understand complex systems and optimize outcomes from different policy and investment decisions. Computer-based models can be used on their own or in support of more qualitative processes like strategic foresight and scenario analysis. Recently, Systems Modelling Tools that integrate diverse infrastructure sectors across a large-scale geographic scope have gained momentum during Strategic Planning phases as they enable decision-making that responds to large-scale interlinkages and dependencies.