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Show I ( (" U-r BHiifiig HIGHWAYS ON PACIFIC COAST Interesting Figures Secured by California Cali-fornia Experts on Pull Required to Move Wagon. An energetic and influential organization organ-ization on the Pacific coast, the California Cali-fornia State Automobile association, has carried on some investigations affording af-fording definite figures of the value of good roads. It secured the help of Prof. J. B. Davidson of the University of California and Austin B. Fletcher, state highway engineer, in carrying on a large number of tests of the pull required re-quired to move a standard farm wagon loaded to make the gross weight 6,000 pounds. This wagon was hauled in some cases by a two-ton truck and in other cases by a team of good draft horses, weighing about 1,600 pounds each. Tests have shown that a pull of 27 to 30 pounds per ton of gross load was needed to haul the wagon on unsur-faced unsur-faced concrete roads. When the concrete con-crete was surfaced with oil and screenings screen-ings the pull was increased to about 50 pounds. About 65 pounds were needed for hauling on water-bound macadam and on bituminous concrete laid on top of cement concrete. On good gravel roads a pull of 65 to 82 pounds was needed, while on loose gravel the pull was 263 pounds, the highest record in any of the tests. ' About 80 pounds were required for hauling on bituminous bitumin-ous macadam. On earth roads 92 pounds were required for hauling over a good surface covered with 1 inches of loose dust, 99 pounds over an ordi- Road Through California Forest. nary dirt road with dust 3 inches deep in places, and 218 pounds over a muddy earth road. The significance of these figures lies in the fact that on a good earth road it Is necessary to exert three times the pull that is required on a concrete con-crete road, and nearly twice the pull required on a macadam road. Furthermore, Fur-thermore, when the earth road becomes be-comes muddy, a condition which does not affect traffic on good pavements, the pull is more than doubled. |