Under sponsorship from the U.S. Department of Transportation Federal Motor Carrier Safety Administration, Office of Bus and Truck Standards and Operations, the John A. Volpe National Transportation Systems Center performed a preliminary research study designed to review English proficiency in relation to safe CMV operation. The study endeavored to learn: 1) The tasks CMV drivers perform that require language comprehension in the interest of safety. 2) The extent to which selected Federal and State enforcement personnel, motor carrier industry groups, individual motor carriers and drivers, State driver licensing agencies and highway departments, and highway safety advocacy groups believe that English language proficiency is necessary for the safe operation of trucks and buses by CMV drivers. 3) How these stakeholders interpret the current FMCSA rule concerning English-language proficiency, and how they believe that a driver's level of English proficiency could be assessed in the licensure and hiring processes, in the daily work environment, and during roadside inspections. 4) Whether stakeholder groups believe that the English-language standard, as currently written, can be applied in a fair and uniform manner. This study took a three-pronged approach of examining available data, observing commercial motor vehicle drivers during their regular schedules, and interviewing a wide range of stakeholders.