The trucking industry’s largest lobbying group recently called for a nationwide 65 mph speed limit, longer trailers and other steps in an effort to cut greenhouse-gas emissions and save billions of gallons of fuel.

Limiting cars and trucks to 65 mph could conserve more than 11 billion gallons of diesel and gasoline over 10 years, the American Trucking Associations said in announcing its sustainability proposals.

That would reduce emissions of carbon dioxide by 116 million tons, the organization said. Carbon dioxide is the chief source of the so-called greenhouse effect and, many scientists say, of global warming.

The trucking group also called for longer combination trailers or higher weight allowances - a proposal likely to draw fire from highway safety advocates - elimination of nearly 500 traffic bottlenecks and government incentives for trucking companies to install devices that reduce idling.