Fisher Coachworks has raised $3.2 million from 10 undisclosed investors of a $4.25 million Series A to develop its hybrid-electric buses, according to a regulatory filing. The Troy, Mich.-based company will put $200,000 of its new-found cash toward salaries and fees and another $500,000 toward the purchase of machinery, according to the filing.Fisher’s first product is a 40-foot bus that it claims weighs half as much as competing buses and delivers twice the fuel efficiency. It’s able to achieve this advancement through the use of Nitronic, a stiffer alloy of stainless steel made by the AK Steel Co.

Fisher has worked with Oak Ridge National Laboratory to test the strength of its welding joints and to simulate crash-responses. The company also won a $2.5 million grant from the Department of Energy’s FreedomCAR and Vehicle Technologies Program.

Innovation in bus manufacturing will likely have a considerable effect on carbon emissions. There are 28 cities in the U.S. that run 400 or more busses during peak transit hours and they accounted for 2.3 billion rides during the first nine months of 2008, according to data from the American Public Transportation Association. That’s up more than 3.2% from the same period during 2007.