British carriages and wagons were designed so the driver sat higher and in the middle or left. Thus making it available to use either hand to coach the horses, though British custom was to use the left hand.
Elsewhere carriage drivers sat lower and due to the obstruction they sat on the left or right of the drivers bench. Since right handedness was the most popular most drivers sat on the left side.
British carriages and wagons were designed so the driver sat higher and in the middle or left. Thus making it available to use either hand to coach the horses, though British custom was to use the left hand.
Elsewhere carriage drivers sat lower and due to the obstruction they sat on the left or right of the drivers bench. Since right handedness was the most popular most drivers sat on the left side.