Drivers operating commercial vehicles across state lines must get a DOT physical if their vehicle weighs more than five tons, is designed to carry 9-15 passengers for compensation, is designed to carry 16+ passengers, or if they are transporting hazardous materials. Drivers must receive a DOT physical every 24 months or as determined by a doctor. The rules for drivers who stay within one state will vary. Check to see if Arizona requires a DOT physical for intrastate driving before booking an appointment.