In this chapter, unless the language or context indicates that a different meaning is intended, the following terms shall have the meanings indicated. Terms Defined. “Carrier” means the holder of a permit. “Carriers of flammables” means any motor vehicle: Common carrier which transports in bulk, in tank vehicles, any liquid which will give off flammable vapors at or below 300 degrees F, or any liquid which, when mixed with wood, sawdust, rags or similar organic substances, will cause spontaneous heating and ignition; and Contract carrier as further defined. “Commission” means the Public Service Commission of Maryland. “Contract carriers of flammables” means and includes any person which, under individual written contracts or agreements of a term or duration of not less than 90 days, within a limited number of persons, engages in the transportation, as a carrier of flammables, in bulk, for compensation within the State. “Operator” means a person engaged in driving a tank vehicle for which a permit has been issued. “Owner” means the individual, partnership, or company to whom a permit has been issued. “Permit” means a permit issued by the Public Service Commission. “Roads” means public streets or highways within the State. “State” means the State of Maryland. “Tank vehicles” includes all vehicles used in the transportation of inflammable or combustible liquids, in bulk, for compensation, upon the public streets or highways within the State.