Assess students' ability to apply quantitative methods to calculate and compare carbon footprints for different transportation options (e.g., single-occupancy car, carpool, bus, train, electric vehicle, bicycle, walking) using given emission factors and trip distances; require per-passenger CO2e calculations, adjustments for occupancy and energy source (e.g., grid intensity for EVs), and brief consideration of lifecycle or modal limitations where relevant. Students must show calculations, state assumptions, compare options across scenarios (short vs. long trips, urban vs. rural), and justify a recommended most sustainable choice based on emissions and contextual trade-offs (time, cost, feasibility).