Graphic representation of distribution of traffic on roads located along section lines.
His analysis assumes the lay of the country makes all roads equally traversable and that the traffic seeks the nearest highway thence to the main traveled road east and west or north and south through the market center. This analysis shows that 4.8 per cent of the total mileage carry 39.3 per cent of the traffic; that 9.5 per cent of the roads carry 71 per cent of the traffic. In his opinion this analysis corroborates the observation of engineers to the effect that 20 per cent of the roads carry 80 per cent of the traffic. Of course the most important roads, measured in traffic, are the ones nearest the market, 15-22, 15-16, 16-21, 21-22. Following these naming only one of the four symmetrical roads, in the order of importance are 14-23, 14-13, 13-24, 13-x, 14-15, 11-12, 12-x, 12-13, 1-x, 11-14, and 1-12.
| Road between Sections | Relative Importance | ||
|---|---|---|---|
| 15 | - | 22 | 100 |
| 14 | - | 23 | 60 |
| 14 | - | 13 | 25 |
| 13 | - | 24 | 20 |
| 13 | - | x | 15 |
| 14 | - | 15 | 13 |
| 11 | - | 12 | 7 |
| 12 | - | x | 7 |
| 12 | - | 13 | 2 |
| 1 | - | x | 2 |
| 11 | - | 14 | 1 |
| 1 | - | 12 | 1 |
The same objections to this method hold as to the preceding. Local conditions always affect the travel on roads; hills, valleys, soil, drainage, nearness to other cities, railways, streams, and location of farmhouses, schoolhouses, churches, and factories, all enter into the estimate. A reconnaissance and the good judgment of the observer must supplement any method of formal procedure.
The Selection of a Suitable Type of Road.
—The highway plan should, if it has been carefully and scientifically made specify the type of roadway as well as the location of the highway. However, when the improvement is to be paid for by a special tax on the abutting land, it is customary to allow the taxpayers to have something to say about the type. Road engineers often object to this as being unscientific and unsound, on the theory that the layman is ignorant of the properties and behavior of road materials and that only an expert can make the proper selection. The author’s observation is, however, that hard-headed business men and farmers who have passed through the experiences of rough knocks are no more likely to make a mistake in the selection of a road type than is the young engineer fresh from the halls of college, or the engineer whose experience has prejudiced him in favor of particular types of road surfacing. The best and fairest of engineers cannot agree, then why not give the man who must pay the fiddler an opportunity to dance?
It will be well, nevertheless, for the engineer to suggest a type, or types, of roadway with his reasons for its or their suitability. If he can show that one type is superior to another the tax-payer will usually follow his advice, and agree to the type suggested. The final decision must rest with the road officials. They should know the requirements of the road, whether, for example, it is to be largely commercial or used largely for pleasure; whether durability or noiselessness is a determining factor; or whether a pleasing appearance and convenience to the inhabitants living along the way are of greater importance than directness and low grades. The decision must be made after taking all things into consideration even to the whims of the property-holders. The best road for a given location is the one which at a reasonable cost will give over a long period of time a service which is most satisfactory to the majority of its users. What is a reasonable cost and what is satisfactory service are debatable questions and usually must be compromised to a greater or less extent.
An ideal road is one that is cheap to construct and maintain, one that is durable, presents light resistance to traffic but is not slippery, is comfortable to travel and not annoying to users or dwellers along its side, and one that is easily cleaned and is sanitary. No road can contain all these qualities to the same degree, neither are they all of equal importance, but each should be given some weight in the selection.
Perhaps the first and most important item to be considered is the economic one of cheapness in construction and maintenance. In making a decision between two types of pavement the first cost will probably have more weight than will the ultimate cost. The fact that a higher priced article will last longer and in the end prove to be a saving has little charm for the man who has not the ready money to pay for the article. He will content himself with the cheaper until he can afford the better. If a community cannot pay for a certain type of road, no matter how desirable that may be, that type cannot be used. Types of roads must be selected which will utilize the materials most available. It would seem to be unwise for brick to be shipped from the Middle West to New England, or granite blocks from New England to the Middle West. Gravel, being plentiful in many states, is being used, and rightly so, more than any other road material notwithstanding the durability of a gravel roadway is less than that of many other types.