was laid out in 1711. In forcing the French from the Ohio Valley about the middle of the eighteenth century, several military expeditions were sent out from Virginia across the Alleghany Mountains. George Washington was one of the first to lay out a military road over this route in 1754, for the purpose of moving Colonel Fry's army. In 1755, General Braddock, of the English Army, in making a similar expedition against the French, followed somewhat the same route as laid out by Washington. There was very little real progress in road-making until the last quarter of the eighteenth century, when the neces sity for more and better roads was met in many cases by the construction of toll roads in various parts of the country. These roads were built and owned by private corporations which exacted payment from those using the road.

The old Lancaster Turnpike, which ran from Philadelphia to Lancaster, Pa., was the first macadam road built in the United States. As originally constructed in 1792, the surface was composed of stones of all sizes thrown together and covered with earth. The roadway became very unsatisfactory, and at a later date it was reconstructed with a macadam surface, no stones being used in the surface that would not go through a 2-inch ring. The success of this type of construction was quickly appreciated, and many of the toll roads constructed up to 1811 were built by this method. By 1811 there were about 4,500 miles of road comprising 317 turnpikes that had been chartered in New York and the New England States. Many of the roads built by private corporations were not a financial success, and whenever abandoned they usually came under the control of the State in which they were located. During the time that toll roads were being built to a large extent, the forced labor system was practically abandoned, but it gradually returned with the decline of the toll roads, and is still in operation in many of the States.

The construction of the Cumberland or National Road by the Government led to some further activity in road-building. This road extended from Washington westward to St. Louis, and was built with a 20-foot width of broken stone, 18 inches

deep at the middle and 12 inches deep at the sides. It was started in 1806, and various appropriations were made for its construction by Congress during a period of over forty years. In certain localities the Cumberland Road was built upon the bed of the road as laid out previously by Washington and Braddock.

Up to 1840 the principal paving used in American cities was cobble-stones. The improvement of highways outside of the cities was retarded for a period of several years beginning with 1837, due to a money stringency. The rapid development of the railroads in this country also served to establish communication between points which otherwise would have been connected by improved highways.

CHAPTER II

PRELIMINARY INVESTIGATIONS

THE design and construction of a road or street should never be undertaken without first making a thorough study of existing conditions. Such an investigation carried out in an intelligent manner may not only result in a great saving in the first cost of the work, but also may preclude the use of certain types of construction which otherwise might be adopted. The purpose of making a reconnaissance for a proposed railway is principally to determine several routes, any one of which may later be selected after careful estimates of cost of construction have been made. In other words, a reconnaissance is mainly a study of location in which curvature, grade, and distance are the main points considered. Location is, of course, important in highway work, but there are many other points just as important, full knowledge of which should be obtained in order to enable the engineer to determine on the most economical and efficacious method of construction.

A preliminary investigation should cover the following essential factors: location, foundation, drainage, æsthetics, width, traffic census, and climatic conditions. The investigation should also cover the following details: normal and abnormal speed of various classes of traffic, the nature of horses' shoes and non-skidding devices used, the traffic regulations in force, the probable change in the character and amount of traffic, the topographical and geological structure and features, the condition and character of cross-roads, the character of existing surface, the possible diversion of traffic, the months available for construction, the availability of materials, the methods of street cleaning and maintenance in vogue, the plant equipment, and the character of available labor.

As considerable ambiguity exists in regard to the meaning

of the terms highway, road, street, boulevard, and pavement as used by many writers, the following definitions are given in order that the use of these terms in this book may be understood.

Highways are the right of ways devoted to public travel, such as alleys, roads, or streets, including the sidewalks and other public spaces, if such exist.

Roads are highways outside of a city, town, or village. The term also refers specifically to the surfacings of the travelled ways or carriageways, when such surfaces are composed of earth, gravel, broken stone, or similar materials.

Streets are highways in a city, town, or village, including the full width between property lines. Streets, therefore, include the carriageways and sidewalks.

Boulevards are usually wide roads or streets constructed with particular attention to æsthetic details and with extraordinary consideration of pleasure travel.

Pavements are the surfacings of the carriageways or footways, when such surfaces are monolithic with a cement or bituminous binder or are composed of blocks.

LOCATION. There are several essentials of good location which, on making a preliminary investigation relative to a proposed highway, will at once be apparent. It is always desirable to eliminate bad grades as much as possible, and in the location of highways without built up districts many opportunities exist to make a decided improvement from this standpoint. Although generally a reduction in grade may considerably increase the cost of construction, there are instances, even in extremely rough country, where a low rate of grade has been obtained without material increase in the cost, provided the property damages are not excessive. In thickly settled communities it is rarely feasible to depart much from the lines of the old highway, but there is so much undeveloped land in the rural districts, particularly of the United States, that the abandonment of the old highway for the purpose of reducing the grade is often an easy matter. Such a desirable change would be apparent by a preliminary examination of the road. The cost of such a change

could only be determined by making careful estimates. Unfortunately, within the city limits, and particularly the very old cities, it is generally impossible to change grades which would be materially improved if the city were being laid out today. In such a case a report on the grade in a preliminary investigation would simply state the rate of grade and the general effect of the grade from the standpoints of use, surface drainage, etc.

What has been said with regard to the elimination of bad grades applies as well to curves. Sharp curves under modern traffic conditions are undesirable from several standpoints. By a judicious relocation of the highway, which many times may only mean a slight shifting of the line, considerable improvement may be obtained. If such changes are thought desirable, it is advisable to confer with abutting property owners to see if satisfactory terms can be made with regard to property damages. Although it is true that many states have the right of eminent domain, it is not tactful to entirely disregard the wishes of property owners, which sometimes deserve serious consideration.

FOUNDATIONS. The foundation on which the road is to rest is of the utmost importance, and hence should receive more than a superficial examination. The failure of many highways has been caused by poor foundations or improper drainage. Of course, in localities where highways have been built for a number of years, experience will have shown what may be expected under certain conditions. In new country, however, where no improved highways exist, the only practical way to gain an idea as to the nature of the soil conditions is. to dig test pits at frequent intervals along the proposed location and to examine the material encountered. Under certain conditions an old earth road-bed may present a very fair appearance at the time it is observed, but there may be other times of the year when this same piece of road would be nothing more than a veritable mud hole, seemingly without bottom. A change of line to avoid bad foundations may be very apparent. Such information is most useful and is the kind that should be sought after. Much can be learned by careful inquiries.

DRAINAGE. Drainage is so closely allied to foundations that