http://www.99mpg.com/projectcars/redlightracingworl/Jake Staub writes "Just replaced the gasoline engine in a Honda Insight with a Diesel engine. On a 3,000 mile cross-country shakedown journey the car averaged 92mpg over 1,800 miles. Around a very hilly town in Northwest Washington, the car is averaging 78mpg. These mileage averages are without the electric side of the vehicle fully functional. With a bit more tinkering on the electric side and through a slight gearing change through tire size, it is anticipated that the car will likely average 100mpg. The build for the car has been documented on the web site and is as close to open source as my time allows. The car was built by two guys in a garage in Southern Maryland. If we can do it I don't see any reason why major auto manufacturers can't do it since we used their parts."