ROADS 149 



drained. Where the road is on a hillside, seepage water, 

 which often causes a wet road, may be intercepted by locat- 

 ing the tile line at the upper side. 



Side Ditches. In the construction of earth roads, side 

 ditches are provided to receive the water and carry it along 

 the road until points are reached where it may be discharged 

 into natural channels. An even grade or slope should be 

 given, so that the water will not collect in puddles in the side 

 ditches. It is impossible to maintain a good road under 

 such conditions. These ditches should be of sufficient 

 capacity to care for the water. They should be so con- 

 structed as not to be dangerous to vehicles when driven into 

 them. The outside bank should not be so steep as to cause 

 the soil to cave into the ditch and partially stop the flow of 

 water. Side ditches should be easily constructed and cleaned 

 with the common road machines. It is desirable that they 

 be of such form as to permit the mowing of weeds in them with 

 a common mower. In some localities it is desirable that the 

 side ditches have a form that will hold snow during the winter 

 months, facilitating sled traffic. A good form for the side 

 ditch is the V shape, with the outside bank having a slope of 

 1J/2 to 1 and the inside bank with a slope of 3 to 1, as shown 

 in the accompanying cross-section of an earth road. 



The Crown. It is highly important that the middle of 

 the earth road be higher than the sides, which will cause the 

 surface water to drain quickly to each side and not lie on the 

 surface and soften it. This oval part of the road is usually 

 called the crown. The road should not only be oval, but 

 should also be smooth so that the water will not lie in pockets 

 on the surface. It is not so important that the crown be of a 

 particular form, except to secure uniformity of construction, 

 but it is important that it be smooth and that there shall be 

 some slope to each side. If the slope be too steep, the travel 



