This interactive D3.js visualization compares simulated car fuel efficiency (MPG) across years 2019–2024, using engine size and vehicle type as axes and color categories. It offers two views: an animated year-by-year transition and a side-by-side small multiples comparison, synchronized with a timed trial feature. The chart uses `d3.csv` to load data, `d3.scaleOrdinal` for color mapping, and SVG rendering with buttons for animation playback and timing. Both views share identical axis ranges and vehicle-type colors, helping users identify upward shifts in MPG for vehicle categories.