Four small-multiple bar charts compare population outcomes across four driving automation modes—Default, Workshop, Shared, and Autonomous—for ten countries. A dropdown menu switches the comparison between pairs of phases. The stacked bars are rendered as SVG rectangles, animated via `transition().duration()`, with axes built using `scaleLinear`, `scaleBand`, `axisLeft`, and `axisBottom` from D3 v5. Data comes from World Population Prospects 2017, loaded from a remote JSON endpoint.