EEPORT OF THE SECEETAEY. 147 



ago were considered entirely satisfactory and firmly established, both 

 in theory and practice, are now often found to be entirely inadequate. 

 In road administration the old principle of extreme localization is 

 fast giving way to new systems involving the principle of centraliza- 

 tion and fixed responsibility. A great deal of careful scientific, as well 

 as educational, work is needed in order to solve correctly the many 

 difficult problems which have arisen in regard to the administration, 

 construction, ajid maintenance of our public roads. This work should 

 prove of the greatest value to the whole country. 



OBJECT-LESSON AND EXPERIMENTAL ROADS. 



The questions which confront road builders vary greatly with local 

 conditions. Instruction in the art of road building to be of real prac- 

 tical value must be adapted to the peculiar conditions of each locality. 

 Such instruction is given by the Office of Public Roads through the 

 medium of object-lesson roads, built at local expense. During the 

 past fiscal year roads were built in 52 places, involving an expendi- 

 ture of approximately $120,000 by the local authorities. The types 

 of road construction included sand-clay, earth, gravel, oiled gravel, 

 plain macadam, bituminous macadam, oil concrete, and slag asphalt. 

 AYhen it is considered that each of these 52 object-lesson roads con- 

 stitutes a practical school of applied road building, it must be evident 

 that this feature of the department's work is a powerful factor in the 

 great Nation-wide movement for the betterment of our public roads. 



ADVISORY WORK. 



For the purpose of giving expert advice concerning specific problems 

 in road work 183 special assignments covering 30 States were made. 

 This work related to such varied subjects as construction of various 

 types of road, surveys, use of prison labor in road work, bridge 

 construction, road maintenance, use of the split-log drag, road ma- 

 terials, effect of automobiles on roads, issuance of bonds for road 

 improvement, road drainage, and other work along similar lines. 

 This is most positive evidence of the wide usefulness of this office, and 

 shows also how generally local communities have come to look upon 

 the Office of Public Roads as a body of consulting engineers and 

 experts capable of offering effective and reliable advice concerning 

 difficult and special problems which are not easily handled by the 

 local authorities. 



MODEL SYSTEMS. 



"Work under the project of model systems has shown a most won- 

 derful increase during the year. Assistance along these lines has 

 been given to 14 counties in 8 States, as against 3 counties in 1910. 

 This is work of the most useful and permanent character. It in- 



