A model for such a force is found in the Pennsylvania State Constabulary, which has been in existence since 1902. This is an organization of two hundred and twenty mounted policemen formed into four companies under a superintendent of police. Every year it patrols 660,000 miles of rural roads and not only keeps the rural sections singularly free from criminals but has performed numerous other distinctive services. It has prevented disastrous fires and mine explosions, quelled riots, stopped illegal hunting and maintained quarantine during epidemics of disease. It was this constabulary that handled the tremendous crowds at the Gettysburg Centennial in 1913. The force is made up of picked men who are taught the laws of the commonwealth and schooled to enforce them with absolute impartiality against offenders of all classes. It has been free from politics and has won the respect of all classes of the people. In the domain of highways[18] the county, under the pressure of the good-roads movement, has been rapidly yielding its control to the central government. The good-roads problem simply outgrew the county. It could not be handled efficiently through so small a unit. In the course of railway development everywhere the old lines of tributary traffic by wagon road from the farms to the shipping centers were greatly modified. Their objective point came to have no particular reference to the boundaries of the county or the location of the county seat. Traffic from one county destroyed the roads of another without supplying any compensatory advantages to the latter. Modern road construction, particularly since the advent of the automobile, created technical engineering problems far beyond the capacity of the local officials to solve. Without the aid of better equipped agencies than a unit so small as the county could afford most of the rural roads of the county must have gone to rack and ruin, to say nothing of their meeting the demands of present day traffic. But forty-two state governments, up to 1915, had come to the rescue, either by supplying financial aid, authorizing the employment of convict labor or by furnishing expert advice founded upon scientific research. Up to the year 1914 only Florida, Indiana, Mississippi, South Carolina, Tennessee and Texas had made no provision whatever for state participation in road work.