Retrieve vehicle fuel economy and environmental data from the EPA FuelEconomy.gov API to enrich vehicle listings

Steps

1. Review the EPA FuelEconomy.gov API documentation to understand the available endpoints for querying vehicles by year, make, model, and trim, and retrieving EPA-rated MPG and CO2 data
2. Query the vehicle menu endpoints to build cascading make/model/year/trim dropdowns that match available EPA records before fetching detailed data
3. Retrieve the fuel economy details for a specific vehicle configuration including city MPG, highway MPG, combined MPG, annual fuel cost estimate, and tailpipe CO2 emissions
4. For electric and plug-in hybrid vehicles, extract the MPGe values and electric range data from the response, which use different fields than ICE vehicles
5. Cross-reference the EPA vehicle ID or trim descriptor with your VIN-decoded vehicle configuration to ensure accurate fuel economy assignment, as EPA records are trim-level not VIN-level
6. Cache EPA fuel economy data aggressively — it changes only when EPA updates its database, typically with each new model year — to reduce redundant calls