From Police Systems in the United States, by Bruce Smith, 1940:
“Its origin was inspired by three apparent needs. The first was that of a general executive arm for the state. The second was closely related to the disturbed industrial conditions in the coal and iron regions, and the demonstrated incapacity of sheriffs, constables, and the organized police forces of small communities generally, to contend with the successfully. The third arose from a realization that the sheriff-constable system had broken down, thereby exposing the rural districts to the danger of inadequate police protection.
“Recognition of all three conditions in Pennsylvania was to have an important bearing upon later police developments elsewhere, but the rural protection aspect challenged attention from the very outset and has exercised a compelling influence upon state police management in many parts of the country from that day to this.
“The distinguishing characteristic of this force consisted in the extensive administrative powers granted to the superintendent of State Police, who was made responsible to the governor of the Commonwealth alone. From the very beginning it operated as a mounted and uniformed body which, using a widely distributed system of troop headquarters and substations as a base of operations, patrolled the rural and semi-rural portions of the entire state, even to the little frequented byways and lanes. In its highly centralized administrative powers, its decentralized scheme of structural organization, and its policy of continuous patrol throughout the rural areas, the Pennsylvania State Police constituted a distinct departure from earlier state practice.”