UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 220 



Contribution from the Office of Public Roads 

 LOGAN WALLER PAGE, Director 



Washington, D. C. 



June 7, 1915. 



ROAD MODELS 



Prepared by the Office of Public Roads 



CONTENTS 



Page 



Introduction 1 



Roman Roads 2 



French Roads 3 



Macadam Method of Construction . . 5 



Telfcrd Method of Road Building ... 6 



Location and Alignment 7 



Foundation, or Subgrade, and Shoulders 7 



Earth and Sand-Clay Roads 10 



Gravel Roads 12 



Page 



Macadam Roads 13 



Cement Concrete Roads 17 



Bituminous Concrete Roads — " Topeka 



Specification" 18 



Paved Roads Other than Concrete ... 18 



Culverts and Bridges 20 



Roadside Treatment 21 



Road Machinery 22 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1915 



