ARLINGTON, Va. — The trucking industry’s adoption of natural-gas vehicles will be driven by favorable economics made possible by a vast domestic supply of the fuel, natural-gas producers and advocates said Thursday at a conference examining the fuel’s potential for transportation, hosted by American Trucking Associations."> ARLINGTON, Va. — The trucking industry’s adoption of natural-gas vehicles will be driven by favorable economics made possible by a vast domestic supply of the fuel, natural-gas producers and advocates said Thursday at a conference examining the fuel’s potential for transportation, hosted by American Trucking Associations.">