70 DESIGN 



and affords a very good footing; furthermore its appear- 

 ance is less artificial. The Roa Hook gravel in particular 

 is of a color which harmonizes well with the natural features 

 of the park. 



Asphalt Paths. This form of pavement is but seldom 

 used. The crown should be as specified for the cement 

 pavement. The foundation is of concrete 3 inches thick. 

 On this is placed a binder course f of an inch in thickness 

 and on this the surface coat also f of an inch thick. The 

 amount of paraffin-petroleum residuum used as a flux in 

 the surface coat should be a minimum in order that the 

 pavement may be as hard as possible. 



Brick Paths. These also are rarely used. The brick 

 may be laid on a concrete foundation with a sand cushion 

 between or may be laid on a bed of cinders leveled off with a 

 layer of sand. The herring-bone bond is preferred. 



DRIVES 



The crown of park drives should be very low, so that the 

 full width of the drive may be effective. For a drive 40 

 feet wide the crown should be about 9 inches. Instead of 

 having a curved profile in cross-section, intersecting planes 

 are recommended as for paths. This permits of driving 

 on the extreme sides of the road. 



Wherever possible, surface water should be carried in 

 grass gutters and not in gutters constructed in the drive 

 itself. 



The effective width of park drives is frequently increased 

 by the construction of wings on both sides. These are made 

 thinner than the middle portion of the drive. 



Park drives are usually constructed on curves rather 

 than on straight lines, although parkway and boulevard 

 drives are sometimes straight. (See Fig. 13, page 41.) 



