150 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Main' worthless road preparations have been and are still being 

 manufactured and sold to the public through ignorance on the part 

 of both the producer and consumer with regard to the character- 

 istics of such materials requisite to meet local conditions. These 

 materials are sold under trade names, and as a rule carry no valid 

 guaranty of quality. Correct specifications for such materials are. 

 therefore, much needed for the protection of the public. 



The influence of the work already done by the office along these 

 lines is shown in the production of better and more uniform materials 

 on the part of the manufacturers. 



"NATiile great progress has been made in the improvement of 

 methods of bituminous road treatment and construction during re- 

 cent years, the subject is still in a stage of development. For this 

 reason the work carried on by the office is of the greatest value to 

 the countr}' in general. Tests and methods of analysis are being 

 standardized, and the behavior of the various materials in actual 

 use is being more definitely determined, while the development of 

 economic and practical methods of construction suitable for various 

 local conditions is being perfected. Much research work along these 

 lines has also been carried on, and will be continued during the 

 coming year. These cover such subjects as the effect of various 

 methods of distillation on the physical and chemical properties of 

 tars, investigations on the economic utilization of various coke-oven 

 tars in the preparation of road binders, studies on the effect of light 

 and the effect of weathering on various bituminous materials, and 

 other allied subjects. 



STATISTICAL AND EC0N0:MIC IN\'ESTIGATI0NS. 



An investigation completed during the year shows that the total 

 road mileage of the United States, exclusive of Alaska and insular 

 possessions, is 2,210,857 miles, of which only 187,910 miles, or 8.49 

 per cent of all our roads, are improved. But in 1004 only 153,531 

 miles, or 7.13 per cent of our public roads, were improved. Thus in 

 the five-year period 1904-1909 the increase in the mileage of our im- 

 proved roads has been 34,379 miles. Investigations to ascertain the 

 economic effect of road improvements on rural communities were 

 begun in 1910 and carried on during the past year. These investiga- 

 tions give promise of exceedingly valuable data and will be continued 

 during the coming year. Investigations dealing with road adminis- 

 tration and road management have been inaugurated during the year. 

 It is believed that when these investigations are completed and pub- 

 lished they will result in the complete reorganization of the present 

 system of road administration in many communities throughout the 

 country. Information is also being collected in regard to taxation, 

 bond issues, and the use of convict labor in road building. This work 

 will be continued during the present year. 



