There are already too many, they're too big and add to deterioration of the nation's highways and bridges.
trucking

Teamsters President Hoffa Says “NO” to Larger Trucks on America’s Highways
Random Thoughts of Chris Tilley - IdleAire

Trying to figure out what this is a picture of?
Well it a systems that allows long haul truckers to turn off their engines when they are parked, keep warm and all their electronics powered.
IdleAire: Reducing Trucker's Environmental Impact
We rely on big trucks to haul stuff across the country for us. But what about when they sit there idling? Not so great for the environment, right? Right. IdleAire has created a device that alleviates the need for idling, while retaining all that truckers are accustomed to having while at rest. Good for the trucks, truckers, and the planet.
Video: NC Researcher Details Freight Emissions
Dr. H. Christopher Frey, Department of Civil, Construction, and Environmental Engineering, North Carolina State University, describes thegreenhouse gas emissions created by freight transport, including trucking and shipping. This seminar is part of a series from theCalifornia Environmental Protection Agency (CA EPA) Air Resources Board.