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Show DAMAGE DONE TO HIGHWAYS Public Roads Bureau Experimenting With Matter of Impact on Various Surfaces. A new series of experiments, which may have a fur-reaching effect upon transportation on the highways and the regulation thereof, has been undertaken un-dertaken by the bureau of public roads, department of agriculture. The work, which is being done by the division of road materials, test and resovrch, is designed to demonstrate demon-strate the damage done to highways by different forms of transportation units traveling under varying conditions. condi-tions. It is thought that the information infor-mation so obtained will perhaps serve as a basis for scientific regulation of traffic on different types of pavements. Incidentally indicating the types and designs of road which will best serve the needs of traffic. It is also suggested that from, this knowledge fair consideration will be assured in legislative charges against Post Road in Maino Built Under Government Gov-ernment Supervision. traffic, since an accurate measure of Impact damage therefrom will be possible. pos-sible. The experiments will cover a wide range, taking into account four factors fac-tors those of speed, height of fall, type of tire used and the weight of the transportation unit. Under the last heading it will be necessary for the bureau to consider distribution of weight above and under un-der springs and on back and front axles, a quantity which is decidedly variable on different makes of motor and horse-drawn vehicles. The bureau has called upon the national automobile automo-bile chamber of commerce to assist In the collection of this data, much of which has not been generally tabulated, tabu-lated, and a questionnaire has been sent to all motor truck manufacturers of America on this subject. Immediate Immedi-ate attention to this has been requested request-ed In order to facilitate the experiments. experi-ments. In the initial stages of the work the pack has been measured by the permanent per-manent deformation of one-half by one-half inch copper cylinders placed under a steel plunger subjected to the :mpact of traffic. A varying height of fall is arrived at by different take-offs for the machine. First experiments indicated a wide range in the force of impact as between units with solid lires and pneumatics. Working from these first steps the bureau officials plan to perfect a machine ma-chine which will take into account the factors mentioned and which will enable en-able them to provide a constant succession suc-cession of impacts on selected slabs or paving compositions. This will enable en-able the experiments to proceed much more rapidly than would be possible under actual road conditions. Tests will be made on horse-drawn as well as motor-driven vehicles. In addition to the above experiments experi-ments another series is planned to determine de-termine the wearing qualities of different differ-ent types of road surfaces when subjected sub-jected to very heavy traffic. |