The word “chauffeur” originally (many years ago) refers to the person who put coal in the locomotives of the steam trains in order to move them forward.
The driver, the one who put coal in the fire, became the driver, and the word kept after the arrival of the gasoline then electric trains.
The analogy was generalized to all vehicles afterwards.
https://www.pourquois.com/francais/pourquoi-conducteur-est-chauffeur.html
https://www.pourquois.com/francais/pourquoi-conducteur-est-chauffeur.html
Being in America 