Fisker Karma Estimated Fuel Economy and Emission Ratings Announced

the technology is over 100 years old , the batteries are the only new thing. BMW just showed it's diesel powered serial hybrid concept.

They would of used the SAE standard for testing a Hybrid-electric vehicle. I doubt they only did 100km in their test run. Probably 500km or more 5x with at least 2 vehicles. I don't know exactly the details couldn't find the procedure online without having to pay....

The SAE standard is fairly complex, and I don't have the updated standard but I do know that it involves partial charge testing, full charge testing, hybrid mode, full electric mode, and full conventional gasoline mode. It takes into account many things such as converting the electrical recharge energy into an energy-equivalent volume of gasoline to add to the actual volume of fuel consumed. Weighting of test results against against US national driving statistics, etc. It really isn't as simple as (in this case) simply multiplying 3.5L by 5 to get 17.5. If the consumption according to the testing is 3.5L per 100km, then it will be so out there in "average American". The average is derived from data collected by the U.S. Federal Highway Administration. To use an apt term, your mileage may vary. ;)