While sales of Class 8 trucks powered by natural gas remain low, U.S. and Canadian natural gas heavy-duty retail sales overall had a healthy start to 2017, boosted mostly from refuse fleets, transit and school bus operators, according to ACT Research Co.

Piedmont Natural Gas said it is adding a third dispenser island at its two-year-old public compressed natural gas refueling station in Nashville, Tennessee, to serve a rapidly growing customer base that includes a mail-delivery contractor and regional haulers taking advantage of the station’s proximity to Interstate 40.

Less-than-truckload carrier FedEx Freight purchased more than 100 compressed natural gas tractors and installed a fueling station to serve the new CNG fleet at its Oklahoma City Service Center, it said.

TruStar Energy said it nearly doubled its number of new compressed natural gas fueling stations for public and private use in 2015 compared with 2014, adding 41 for a total of 120 stations.

Saddle Creek Logistics Services said its compressed natural-gas fleet of 200 heavy-duty trucks reached the 50 million-mile mark in October. It also recently completed a $1.5-million upgrade to the CNG fueling facility at its Lakeland, Florida, headquarters, by adding more efficient time-fill stations.

Chevrolet is introducing a dual-powered Silverado, run on either compressed natural gas or gasoline.

The trucking industry’s adoption of natural gas has slowed in the past 18 months as diesel prices declined, but analysts and fleet executives maintain the alternative fuel will play a larger role in freight transportation over the longer term.