The Transit Costs Project team recently published eight data visualizations that help make sense of their larger dataset, which includes more than 600 urban rail projects in more than 50 countries. They explore how costs vary by country, speed of construction, length of the line, and change over time. They have also accounted for differences in elevated, at-grade, and tunneled construction. While these visualizations don’t explain why costs vary from one country to another, they underscore how knotty this work is because even expected correlations, such as a positive relationship between GDP and costs, don’t show up in the data.
These visualizations reveal the need for more research and that the team’s in-depth case studies are an important complement to help understand why costs differ from one country to another.