Does residential segregation align with urban barriers?

Previous research has shown that residential segregation aligns with urban fragmentation in cities with explicit segregation policies, but this relationship remains untested in other contexts. Here we analyze 520 cities across eight Western European countries using high-resolution demographic data and a Monte Carlo approach to test whether residential segregation of non-EU migrants aligns with urban fragmentation by railways, motorways, and waterways. We find no systematic alignment between residential segregation and urban barriers across European cities. Instead, many cities exhibit significantly less alignment than would be expected by chance. We identify important regional variations, with cities in Germany and the Netherlands showing stronger alignment than other countries. These findings suggest that urban barriers do not generally function as social frontiers in European contexts, with country-specific urban development potentially influencing the observed regional differences.