ROADS AND BRIDGES 289 



In cases where much grading is necessary the road- 

 way should be surveyed and stakes placed at either 

 side of the proposed road. On stakes at the sides of the 

 roadway are placed figures showing how deep to cut or 

 how deep to fill at each successive point along the line 

 of the road. Diagrams should also be made showing the 

 width of the road bed and the slope of the banks in cuts 

 and in fills. Frequently the width for the road can be 

 determined only with a knowledge of several factors; 

 the importance of the road and the amount it is used, the 

 means available for its construction, the kind of surfac- 

 ing material to be applied, and the volume of water to 

 be carried by the ditches beside the road. The slant 

 to be given the banks in cuts, or slope on the sides of 

 the grades in fills, will be determined by the character 

 of the material of the banks. Solid rock may be left 

 vertical, loose sand or running clays must have a very 

 low slant. Ordinary mixed earth of sand and clay re- 

 quires a slant of 30 to 45 degrees according to its ability 

 to stand. Sometimes fertile soil which will retain 

 moisture may be placed on the surfaces of embank- 

 ments and planted to grasses, which will prevent them 

 from being washed down by rains. 



Specifications for the surface. While hauling the heavy 

 material for surfacing has become a comparatively simple 

 matter, few road contractors or superintendents under- 

 stand how to secure the best material for the surface or 

 how to place it on the roadway in the best manner. There 

 is greater need of engineering knowledge and experience 

 at this point than at any other. The available materials 

 are so varied in character and may be combined in so 

 many ways that the plans for making the earth road, the 

 gravel surface, or even the macadam roadway, cannot 

 usually be made in a theoretical or offhand way. In 

 some cases, the most economical and best way for man- 

 aging the construction of the road surface can be deter- 



