German vehicle manufacturer Daimler on Monday presented 16 hybrid trucks and buses as part of a new global initiative to reduce fuel consumption and emissions.

The vehicles from the Freightliner, Mitsubishi Fuso, Mercedes-Benz, Orion and Thomas Built Buses lines include conventional hybrids as well as so-called "series" hybrids, which use only the electric motor to propel the vehicles.

The company also unveiled a Mercedes-Benz hybrid that uses wheel-hub motors, which it said could help transition from diesel engines into fuel cells.

The move, part of what the company is calling its Shaping Future Transportation initiative, combines hybrid and diesel technology.

Hybrid technology mainly has been used with gasoline. But because diesel fuel already gets more miles per gallon than gasoline, some analysts have said a combination of diesel and hybrid technology could prove successful.

Daimler is late to the hybrid game, having instead emphasized its clean-diesel technology before announcing it was partnering with BMW to develop hybrids in March.

The company claims its hybrid technology can reduce diesel consumption by up to 30 percent in these commercial vehicles. The auto titan also said it is investigating the possibility of using alternative fuels, including those derived from vegetable oils and biomass.

The announcement comes only one business day after California sued the U.S. Environmental Protection Agency over its request to set stricter emissions from vehicles (see In Brief: California Sues EPA for Greener Vehicles).

The state passed a law in 2002 to reduce vehicle emissions by 30 percent by 2016, but automakers sued the state -- along with others trying to tighten transportation emissions laws -- in 2004, effectively blocking the law so far.

The Daimler news isn't the only evidence that hybrids could be spreading to heavy-duty vehicles.

Railpower Technologies Corp., which makes hybrid locomotives, announced Friday that it had raised $35 million from the Ontario Teachers' Pension Plan (see this Cleantech Investing post).