DUST PREVENTION AND ROAD PRESERVATION, 1916. 67 
AMES, IOWA, 1910. 
OIL-ASPHALT GRAVEL. 
ResumME or Previous Reports. 
This experimental road was built in September, 1910. The work 
consisted in resurfacing a 300-foot section of gravel road in the 
grounds of the Iowa State Agricultural College. The old gravel 
road had a thickness of 6 inches and was in good condition when the 
work was begun. A portion of the traffic was automobile. Table 
68 shows the condition of the experiment at various times since its 
construction. The results shown have been taken from the reports 
of inspection made by this office, published in Circulars Nos. 94, 
98, and 99, Office of Public Roads, and in Bulletins 105, 257, and 407, 
U. S. Department of Agriculture. 
