Hydraulic hybrid technology is moving ahead on a series of fronts, building on its commercial successes with garbage trucks and parcel delivery vehicles.

Now the focus is on proving actual day-to-day performance in these heavier vehicles, where the high power density of fluid power technology shines the best, while laying the groundwork to move the technology into lighter vehicles.

This year, the big news for hydraulic hybrid technology came when Environmental Protection Agency administrator Lisa Jackson and Chrysler CEO Sergio Marchionne announced a cooperative agreement to develop and adapt the technology for the light-duty auto market. Using the EPA's own patented technology, the partnership's goal is to move the technology from the lab to the street and design a Chrysler minivan as a demonstration vehicle.

Expectations are that hydraulic hybrid technology can increase fuel efficiency 30-35 percent overall and up to 60 percent in city driving, and reduce overall greenhouse gas emissions by 25 percent.

The EPA is a leader when it comes to developing hydraulic hybrid technologies, specifically series hydraulic hybrid systems. The EPA has been working on them since the late 1990s, teaming with manufacturers such as Eaton and Parker Hannifin.