Where can one compare the miles per gallon or fuel economy of different vehicles?

The official source for comparing the miles per gallon (MPG) or fuel economy of different vehicles in the United States is the Fuel Economy website managed by the U.S. Department of Energy. Here's how you can use this website to compare fuel economy:

1. Go to the Fuel Economy Website: Open a web browser and navigate to the Fuel Economy website: www.fueleconomy.gov.

2. Select "Compare Side-by-Side": On the homepage, click on the "Compare Side-by-Side" button located at the top of the page.

3. Choose Vehicles: Enter the names or models of the vehicles you want to compare. You can add up to three vehicles for comparison.

4. Fuel Type and Use: Select the fuel type (gasoline, hybrid, electric, etc.) and the intended use (city, highway, combined) for each vehicle.

5. View Results: Click on the "Compare" button to view a detailed side-by-side comparison of the vehicles' fuel economy, including MPG estimates for city, highway, and combined driving.

6. Additional Information: The website provides additional information such as the annual fuel cost, fuel tank capacity, and environmental impact ratings for each vehicle.

Remember, the fuel economy estimates provided on the Fuel Economy website are based on standardized tests conducted by the EPA and may differ from real-world driving conditions. However, they offer a reliable basis for comparing the fuel efficiency of different vehicles.