Due to a lack of central organizing oversight, many routes were legislated, but not numbered.
This was bolstered in 1894 with the creation of a Commissioner of Public Roads, which evolved into the State Highway Commission in 1909.
The first effort at a state-wide highway network was begun by the commission in 1912 and submitted for approval in 1913.
However, after 1921, the process was less coordinated, as local politicians tried to get their route built without concern for duplication of numbers.
The State Highway Commission was not allowed to change the numbers; the best they could do was assign suffixes.