Rubber hits the road . . .

Tractor-trailers operating with single wider tires recorded improved fuel efficiency numbers between 7.2 and 10 percent when compared to rigs operating on standard-sized dual tires.

A year-long truck performance study managed by Oak Ridge National Laboratory's Heavy Truck Safety Research program concluded that trucks carrying payloads up to the federal weight limit of 80,000 pounds had improved miles-per-gallon diesel savings because the wider tires had better rolling resistance performance.

The study involved instrumenting a fleet of tractor-trailers accumulating 700,000 miles, making it the most extensive public study yet involving single wider tires. Previous studies by ORNL that involved less data to work with indicated improved fuel efficiency of only 3 percent.

The funding source is the DOE Office of Vehicle Technologies.