This visualization compares average emergency response times across San Francisco neighborhoods, separating alarm and fire incidents by color-coded bundles. Animated stacked bars update when a user selects a year from the dropdown or toggles sorting. Built with D3 v5, it uses `d3.nest()` and `d3.layout.stack()` to aggregate CSV data, `d3.scaleOrdinal` for the categorical color mapping, and SVG transitions for the year-driven updates.