This stacked bar chart shows the average annual traffic count for Allegany County, New York, broken down by road type from 1977 onward. Using D3 v6 within a React framework, the visualization renders as SVG rectangles, with the `d3.stack` API grouping data by year and road type (0, 1, 2). The chart employs `d3.scaleTime`, `d3.scaleLinear`, and `d3.scaleOrdinal` for axes and color encoding, with data loaded from a CSV file via `d3.csv`.