Hybrid and electric cars are increasingly becoming the hottest new cars of the future. And while Japan may seem to be leading the way, AOL Autos shows that judging fuel efficiency of cars may be a bit more complicated than it seems.

Rather than judge a car by its general reputation or even its government-measured Corporate Average Fuel Economy (CAFE), the savvy consumer should check miles per gallon (mpg) numbers.

Let’s start with what the Environmental Protection Agency (EPA) says in its current ranking. While many consumers believe Honda and Toyota top the fuel economy rankings, Hyundai actually has had the highest fleet-wide fuel economy since 2008. Last year, its fleet averaged 25.9 mpg. Honda was #2 with 25.6 mpg. Kia was no. 3 with 25.1 mpg. Volkswagen scored 24.6 mpg (helped a lot by its clean-diesel vehicles that get greater fuel economy than gas-fueled cars). Toyota was no. 5 with 24.5 mpg. The top Detroit automaker was GM in 11th place, with a fleet-wide average of 20.8.

The most fuel efficient mid-sized Sedan?

Winner: Hyundai Sonata: 28 mpg
2. Nissan Altima and Honda Accord: 27 mpg
3. Toyota Camry and Ford Fusion: 26 mpg
*Best alternative drive-train: Ford Fusion Hybrid: 39 mpg
**Chevy Volt is an extended range electric that gets a combined 37 mpg when running on gasoline. It goes up to 40 miles on an electric charge depending on driving technique.

Anyone can check out car fuel efficiency on the government website, www.fueleconomy.gov.

For complete AOL Autos rankings on best compact SUV, pickup truck, full size SUV and hatchback, check out the full story.

Another surprising fact: Porsche innovated the technology for hybrid vehicles by reducing the weight of car batteries.

Reconstruction of the historic Lohner-Porsche Semper Vivus hybrid took four years and, in a recent press release, Porsche states that this was the world’s “first functional hybrid car.” That statement leads us to believe that the idea of a gas/electric hybrid was certainly not new at the time, but that Dr. Ferdinand Porsche was the one who actually made the whole thing work.

One of the big problems for Dr. Porsche was weight. Ask Nissan, Ford or Chevrolet about their recent electric or hybrid cars and they’ll tell you that’s still an issue. Batteries and electrical components are heavy. Porsche continued to work on reducing the hybrid’s weight from the year 1900 through 1905. The total weight of the reconstructed Semper Vivus is 1.7 tons. The vehicle’s top speed is 22 mph and it has a total range of about 124 miles, fairly impressive for 1900.

Read the full story on Porsche hybrids.

Picture: An employee of Nissan Motor demonstrates how to plug in the electric vehicle ‘Leaf’ at the company’s showroom in Yokohama, suburban Tokyo on February 9, 2011. AFP PHOTO / Yoshikazu TSUNO