126 HIGHWAY CONSTRUCTION 



inch of overlying dirt will most effectually protect the pavement from 

 abrasion, and indefinitely prolong its life. But the dirt is expensive, 

 it injures apparel and merchandise, and is the cause of sickness and 

 discomfort. In the comparison of different pavements, no traffic 

 should be credited to the dirty one. 



Life of Pavements. The life or durability of different pavements 

 under like conditions of traffic and maintenance, may be taken as 

 follows : 



Life Terms of Various Pavements 



Cost. The question of cost is the one which usually interests 

 taxpayers, and is probably the greatest stumbling-block in the attain- 

 ment of good roadways. The first cost is usually charged against the 

 property abutting on the highway to be improved. The result is that 

 the average property owner is always anxious for a pavement that costs 

 little, because he must pay for it, not caring for the fact that cheap 

 pavements soon wear out and become a source of endless annoyance 

 and expense. Thus false ideas of economy always have stood, and 

 undoubtedly to some extent always will stand, in the way of realizing 

 that the best is the cheapest. 



The pavement which has cost the most is not always the best; nor 

 is that which cost the least the cheapest ; the one which is truly the cheap- 

 est is the one which makes the most profitable returns in proportion to the 

 amount expended upon it. No doubt there is a limit of cost to go be- 

 yond which would produce no practical benefit ; but it will always be 

 found more economical to spend enough to secure the best results, and 

 this will always cost less in the long run. One dollar well spent is 

 many times more effective than one-half the amount injudiciously 

 expended in the hopeless effort to reach sufficiently good results. The 

 cheaper work may look as well as the more expensive for the 

 time, but may very soon have to be done over again. 



Economical Benefit. The economic benefit of a good roadway is 



