770 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Experience has sho\\Ti that earth roatls can be greatly improved 

 by ])ropcr construction and systematic maintenance at a cost well 

 within tljc reacli of nractically ovory conHnvinity and, since 90 to 95 

 per cent of the total mileage of roads must remain earth roads for 

 years to come, the Office is encouraging the improvement of this 

 type of highways. In the past water-bonded macadam has been 

 used extensively for surfacing earth roads, but, when subjected to 

 heavy automobile trallic, this surface raj)idly disintegrates. Fairly 

 successful efforts have been made to fina a means of preserving the 

 roads already surfaced and to develop a kind of construction that 

 will be suitable for the changed conditions of traflic. The table given 

 above illustrates to what extent these policies have been carried out. 



BITUMINOUS MACADAM ROADS. 



Atlanta, Ga. — The work at Atlanta, Ga., consisted of gradinj» and surfacinjj with 

 bituminous macadam a section of the Teachtree road. Work was begun October 18, 

 1909, and completed June 25, 1910. Prior to October 18, 1909, the local authorities 

 had partially graded 9,700 lineal feet of the road. This was completed and G,144 

 cubic yards of earth were moved between stations 97+00 and 114 -f- 50 at a cost of 

 $1,280.24; 11,529 cubic yards of stone were quarried at a cost of $4,863.85, or 42.2 cents 

 per cubic yard, and crushed at a cost of .'S820.37, or 7.1 cents per cubic yard; 8,080 

 cubic yards of stone were hauled with hauling engines an average distance of 9,500 

 feet at a cost of $687.10, or 8.5 cents per cubic yard. The stone was spread in two 

 courses: The first, 5.5 inches in depth, contained stones from 2 to 3.5 inches in size; 

 and the second course, 5 inches in thickness, contained stones from 0.75 inch to 2 

 inches in size. After these two courses of stone had been thoroughly rolled, tar was 

 applied at the rate of 2.55 gallons per square yard. The cost of applying 41,626 

 gallons was $718.48 and the cost of the tar was $2,081.30, or 5 cents per gallon. Three 

 hundred and five cubic yards of chips and screenings were used. ^\'ith labor at from 

 50 cents to $1.75 per day, convict labor at 50 cents per day, county teams at 75 cents 

 per day, and fuel at from $1.80 to $3.50 per ton, the total cost of the work done was 

 $19,336.58. No cost per square yard is available, as the work was begun before this 

 Office had anything to do with this road and was continued after participation in the 

 work by this Office had ceased. 



El Paso, Tex. — The work at EI Paso, Tex., consisted of supervising the resurfacing 

 of 23,470 square yards of old macadam road, and preparing plans and specifications 

 for 112 miles of new construction, including a number of reinforced concrete bridges. 

 The work of resurfacing was begun May 10, 1909, and entirely completed July 22, 1909. 

 The dust was first swept off with wire brooms and the roadway spiked up viath a road 

 roller. The road was then shaped and given a crown of one-half inch to the foot, 

 wet and rolled. A course of clean limestone, broken in sizes of from three-fourths of 

 an inch to 1^ inches, was then spread upon the road to a depth of 3 inches, measured 

 loose, and lightly rolled. Care was taken that the stone should remain free from 

 dust and moisture. Asphalt, heated to about 300° F., was then evenly spread over 

 the surface of the road, with flat nozzle sprinkling cans, at the rate of 15 pounds per 

 square yard. Stone chips, one-half inch in size and free from dust, were then spread 

 upon the road in sufficient quantity to fill the voids of the larger stone and were swept 

 into place. The road was then thoroughly rolled and sufficient screenings were 

 spread upon the road to take up any surplus asphalt. The cost of this work was as 

 follows: Furnishing and rolling into place 2,525 cubic yards of stone, $4,923.98; 

 furnishing 193.8 tons of asphalt, $3,882.22; cost of labor, $1,538; making a total cost 

 of $10,344.20, which is at the rate of 44.08 cents per square yard. 



PnoENix, Ariz. — An oil macadam road 3,250 feet in length and 16 feet wide was 

 built at Phoenix, Ariz., between March 14, 1910, and May 7, 1910, during which 

 twenty-four days were lost because of the failure of the contractor to deliver stone. 

 The land over which the road was built is practically level and all earth was moved 

 with a road grader. The local authorities furnished a 10-ton macadam road roller, 

 two improved road oilers, two tank wagons, and a road grader. Fourteen hundred 

 and thirty-si.x cubic yards of stone were delivered by contract on the road at a coat of 

 $1.67 per cubic yard. The stone was spread in four courses. The first course, 5^ 

 inches thick, was of stone between 1^ and 4 inches in size, with the voids filled with 

 gravel. The second course, 2 inches thick, was of stone from three-fourths of an inch to 



