This stacked bar chart visualizes traffic counts across 28 lane segments, categorizing volumes into pedestrians, non-motorized vehicles, and motor vehicles by lane ID. Animated on page load, hovering over any bar segment reveals a tooltip displaying the exact count and percentage share of that category within the total for its lane. Built with React and D3 v6, it uses `d3.stack()` to generate the layered series, `d3.scaleBand()` and `d3.scaleLinear()` for positioning, and `d3.scaleOrdinal()` with `d3.schemeSet3` for color encoding. A custom HTML legend and SVG-rendered axes complete the visualization.