Do you need a Medical Examiners Certificate to drive a commercial vehicle under 26001 lbs?

Any CMV with a Gross Vehicle Weight Rating in excess of 10,000 lbs. and which is being operated across state lines requires a current and valid DOT medical card. Any vehicle under 26,000 GVW which is a bus designed to transport more than 15 persons (including the driver) requires a CDL, ergo it requires a medical card. Same with any vehicle carrying a quantity of hazardous materials which requires placards to be displayed.