E-commerce is fueling pollution by putting more commercial delivery vehicles on the road, but hybrid trucks could solve that problem, U.S. researchers say. \"Buses and trucks, particularly vehicles used to transport goods, represent a huge percentage of global fuel consumption and tailpipe emissions,\" Gregory Shaver, an associate professor of mechanical engineering at Purdue University, said. \"Growth in e-commerce is one phenomenon leading to significant increases in the number of trucks needed to transport goods.\" E-commerce spending grew dramatically in 2010 adding to increasing fuel consumption for commercial vehicles, he said in a Purdue release Wednesday. Perfecting hybrid trucks could help control emissions and cut fuel consumption in half, he said. Shaver is principal investigator of the new Hoosier Heavy Hybrid Center of Excellence, funded with a $1 million grant from the U.S. Department of Energy to research ways of reducing fuel consumption for commercial vehicles by perfecting hybrid technologies for the world\'s burgeoning bus and truck fleets. The United States is the world\'s largest oil user, consuming nearly 20.7 million barrels per day.