Highways and Highway Transportation

by George R. Chatburn

The Procedure of Laying out a Road System.

—To fix the mind definitely suppose it to be a state road system that is to be laid out. It is generally conceded that the planning should be done by an unprejudiced commission headed by an engineer of wide experience, one who is fair but will show no favoritism. The first question, after deciding to make a layout and who shall make it, is what shall be the determining factor of the lay-out. Shall it be primarily a farm to market system, primarily a commercial system, or primarily a recreational system? A wise commission will, no doubt, attempt to embody all these features in one system, as they should be, for, nowadays, more than half the population of the country reside in the cities and villages. They pay taxes and are as much entitled to road facilities for their particular industries and pleasures as are the “farm bloc,” and every fair-minded person will admit this.

Good maps must of course be obtained. Government contour maps when available will assist materially in selecting roads that will come within a ruling grade. On these maps will first be noted the trunk line terminals and other ruling points. The trunk lines should be as direct as practicable from one ruling point to the next. An endeavor should be made to have the roads with the greatest travel upon them the straightest, so that the total future haul may be a minimum. The roads having the greatest travel will usually be those connecting the largest cities of the state or articulating with roads leading to large cities of other states. Then will be drawn in branch lines and detours so that when the plan is complete every county seat, every village of more than 1000 inhabitants, and every manufacturing, scenic, and pleasure resort of importance will have been reached, as well as connections with the main roads of adjacent states.

This will form a tentative system. Observation upon the roads themselves will now be necessary. A reconnaissance survey may be made quite rapidly from an automobile. Two men are necessary. The engineer will ordinarily drive while the topographer will be supplied with a clip board and ruled sheets of paper. The straight line up the center of the sheet represents the roadway. Small squares on the sheets represent distances and areas. The scale should be made according to the work. On a road with few houses and few topographical features to be recorded 1 inch to the mile might be sufficient. With more houses, and other features, 1 inch to the quarter mile might be none too much. As speedometers (odometers) usually read to a tenth of a mile cross-section paper with ten smaller divisions equal to one larger is convenient. The engineer will observe features and the recorder will record them as the machine is driven along. The miles may be marked off on the sheets ahead then very quickly by a series of notations, such as a

for a farm house, a dot with a roof over it

for a school house, a steeple or cross on top

makes a church. A crossing wagon road

, railroad track

, a trolley line

, stream

, and so on. Written explanations can be made along the margin where necessary.

The reconnaissance survey should cover all routes on the tentative map together with alternative or competitive routes and others when found to be worthy of consideration. The record will show all farm houses within a prescribed limiting distance of the roadway, factories, stone quarries, sand and gravel pits, schoolhouses, and churches. All intersecting roads, railroads, trolleys, mail routes, creeks, canals, rivers, drainage and irrigation ditches, culverts and bridges, together with the approximate angle of crossing the highway. Note should be made whether grade crossings may be eliminated by underground or overhead crossings, or by change of route. The character of the soil whether clay, loam, gumbo, or sand, when it differs from the general run of soil should be recorded, also hills, swamps, bad condition generally with brief notes as to how they may be bettered. Turns in the road itself may be noted by an angle thus

,

,

,

. Where no turn is shown, straight away is understood. Other information and natural or artificial features that may prove interesting or helpful will suggest themselves for record as the survey proceeds. Of course the mileage of each route as measured by the odometer or speedometer from fixed and known points on the map will be taken. By tabulating and mapping the information recorded it will be possible to get at the comparative merits of alternative routes.

A few simple surveying instruments will be useful in the work of reconnoitering. A steel 100-foot tape, a hand level and inclinometer, a pedometer, a pocket compass, a small aneroid barometer in mountainous countries, a pioneer ax for blazing, and a small spade may be mentioned.

After the reconnaissance, hearings should be held, usually at county seats, notice of such hearings having been given ahead of time. At these hearings the maps are shown and a statement made relative to the procedure. After which an invitation for suggestions and constructive criticism and even complaints is given. From these people who are locally interested in the roads many valuable suggestions will be received, and if they cannot be followed the reasons therefor may be stated. The people will thus know the investigation and the location of the road have been fairly made and that any suggestions that cannot be settled offhand will be duly considered before final location.

The final location will usually be arrived at or at least influenced by the following considerations: Alignment and distance, population served, grades, amount and character of haulage, other kinds of transportation available, character of soil (sand, clay, gumbo, loam), structures, bridges, railroad grade crossings and their possible avoidance, discovery of entirely new routes, topography, geological formation, and other natural features and numerous local conditions, including availability and freight charges of road materials. These are not intended to be in the order of importance, for no two roads may have the same determining factors. The character of the road surface to be used in construction may greatly affect the location. For example it does not pay to use steep grades with hard smooth pavements. But steeper grades may be used with earth and gravel roads without material loss in efficiency.

It will seldom be necessary to resort to preliminary or complete survey to lay out the plan. Sometimes further viewing of alternative roads may be desirable and many times compromises will have to be made. A traffic census on the several routes would be extremely valuable for it would determine to which class, agricultural, commercial, or recreational, the road belongs, and also the character of the traffic and what type of construction is best suited. Especially where there are alternative roads, as is usually the case in midwestern states where the roads were established along the section lines of the U. S. land survey, it is very difficult to determine which is the important highway without a traffic census. It must be remembered, however, in this connection that the improvement of a road will often draw to it much traffic from an equally short competing line. It is quite likely that if 10 per cent of all roads, provided they are properly selected, should be well improved they would carry 90 per cent of all traffic.