Economical Benefit. The economic benefit of a good roadway is comprised in its cheaper maintenance; the greater facility it offers for traveling, thus reducing the cost of transportation; the lower cost of repairs to vehicles, and less wear of horses, thus increasing their term of serviceability and enhancing the value of their present service; the saving of time; and the ease and comfort afforded to those using the roadway.
First Cost. The cost of construction is largely controlled by the locality of the place, its proximity to the particular material used, and the character of the fdundation.
The Relative Economies of Pavements—whether of the same kind in different condition, or of different kinds in like good condition —are sufficiently determined by summing their cost tinder the following headings of account: (1) Annual interest upon first cost. • (2) Annual expense for maintenance.
(3) Annual cost for cleaning and sprinkling.
(4) Annual cost for service and use.
(5) Annual cost for consequential damages.
Interest on First Cost. The first cost of a pavement, like any other permanent investment, is measurable for purposes of comparison by the amount of annual interest on the sum expended. Thus, assum ing the worth of money to be 4%, a pavement costing 34 per square yard entails an annual interest loss or tax of $0.16 per square yard.
Cost of Maintenance. Under this head must be included all out lays for repairs and renewals which are made from the time when the pavement is new and at its best to a time subsequent, when, by any treatment, it is again put in equally good condition. The gross sum so derived, divided by the number of years which elapse between the two dates, gives an average annual cost for maintenance.
Maintenance means the keeping of the pavement in a condition practically as good as when first laid. The cost will vary considerably depending not only upon the material and the manner in which it is constructed, but upon the condition of cleanliness observed, and the • quantity and quality of the traffic using the pavement.
The prevailing opinion that no pavement is a good one unless, when once laid, it will take care of itself, is erroneous; there is no such pavement. All pavements are being constantly worn by traffic and by the action of the atmosphere; and if any defects which appear are not quickly repaired, the pavements soon become unsatisfactory and are destroyed. To keep them in good repair, incessant attention is
necessary, and is consistent with economy. Yet claims are made that particular pavements cost little or nothing for repairs, simply because repairs in these cases are not made, while any one can see the need of them.
Cost of Cleaning and Sprinkling. Any pavement, to be con sidered as properly cared for, must be kept dustless and clean. While circumstances legitimately determine in many cases that streets must be cleaned at daily, weekly, or semi-weekly intervals, the only admis sible condition for the purpose of analysis of street expenses must be that of like requirements in both or all cases subjected to comparison.
The cleaning of pavements, as regards both efficiency and cost, depends (1) upon the character of the surface; (2) upon the nature of the materials of which the pavements are composed. Block pave ments present the greatest difficulty; the joints can never be perfectly cleaned. The order of merit as regards facility of cleansing, is: (1) asphalt, (2) brick, (3) stone, (4) wood, (5) macadam.
Cost of Service and Use. The annual cost for service is made up by combining several items of cost incidental to the use of the pave ment for traffic—for instance, the limitation of the speed of movement, as in cases where a bad pavement causes slow driving and consequent loss of time; or cases where the condition of a pavement limits the weight of the load which a horse can haul, and so compels the making of more trips or the employment of more horses and vehicles; or cases where conditions are such as to cause greater wear and tear of vehicles, of equipage, and of horses. If a vehicle is run 1,500 miles in a year, and its maintenance costs $30 a year, then the cost of its maintenance per mile traveled is two cents. If the value of a team's time is, say, $1 for the legitimate time taken in going one mile with a load, and in consequence of bad roads it takes double that time, then the cost to traffic from having to use that one mile of bad roadway is $1 for each load. The same reasoning applies to circumstances where the weight of the load has to be reduced so as to necessitate the making of more than one trip. Again, bad pavements lessen not only the life-service of horses, but also the value of their current service.