Pike Research, a clean technology market intelligence company, said global managers could add as many as 4 million hybrid electric vehicles to their fleets between 2009 and 2015.
The research company said hybrid vehicles sales are growing substantially in corporate and government fleets as so-called green technology gains support and recognition.
"Manufacturers are beginning to turn their attention beyond light duty vehicles to the efficiency opportunities for hybrid drive in heavy trucks," said Pike Research Managing Director Clint Wheelock.
Pike Research said hybrids have a fuel economy that is between 10 percent and 40 percent better than conventional vehicles.
North America, said Wheelock, will lead the pack with an 8-percent gain in hybrid-vehicle purchases during the next five years. The Asia-Pacific region, meanwhile, should expand its interest in hybrids, but at a lower level compared with North America.