https://www.law.cornell.edu/cfr/text/29/782.3#:~:text=MC%2D4%2C%201%20M.C.C.%201,in%20interstate%20or%20foreign%20commerce.

Driver means any person who operates any commercial motor vehicle.

https://www.law.cornell.edu/cfr/text/49/390.5

So, at the very least, this is true for interstate travel -- but may not be true for state/local roads.

https://www.law.cornell.edu/cfr/text/29/782.3#:~:text=MC%2D4%2C%201%20M.C.C.%201,in%20interstate%20or%20foreign%20commerce.