HIGHWAY CONSTRUCTION 



123 



(9) It should be easily cleaned. 



(10) It should be cheap. 



Interests Affected in Selection. Of the above requirements, 

 numbers 2, 4, 5, and 6 affect the traffic and determine the cost of haul- 

 age by the limitations of loads, speed, 

 and wear and tear of horses and ve- 

 hicles. If the surface is rough or the 

 foothold bad, the weight of the load 

 a horse can draw is decreased, thus ne- 

 cessitating the making of more trips or 

 the employment of more horses and 

 vehicles to move a given weight. A 

 defective surface necessitates, a reduc- 

 tion in the speed of movement and 

 consequent loss of time; it increases the 

 wear of horses, thus decreasing their 

 Fig. 78. imprint Roller. iif e se rvice and lessening the value of 



their current services ; it also increases 

 the cost of maintaining vehicles and 

 harness. 



Numbers 7, 8, and 9 affect the 

 occupiers of adjacent premises, who 

 suffer from the effect of dust and 

 noise; they also affect the owners of 

 said premises, whose income from 

 rents is diminished where these disad- 

 vantages exist. Numbers 3 and 10 af- 

 fect the taxpayers alone first, as to 

 the length of time during which the 

 covering remains serviceable; and sec- 

 ond, as to the amount of the annual 



repairs. Number 1 affects the adjacent occupiers principally on 

 hygienic grounds. Numbers 7 and 8 affect both traffic and occupiers. 

 Problem Involved in Selection. The problem involved in the 

 selection of the most suitable pavement consists of the following 

 factors: (1) adaptability; (2) desirability; (3) serviceability; (4) dura- 

 bility; (5) cost. 



Adaptability. The best pavement for any given roadway will 



Fig. 79. Impi-int Roller. 



