ROAD BUILDING AND MAINTENANCE INVESTIGATION.

Object-lesson roads were built of sand-clay construction at Tarboro, N. C.; top-soil construction in Henry County, Va.; and gravel construction at Austin, Tex.

The superintendence of the construction of county roads was conducted in Sussex and Albermarle Counties, Va.

The following-named State highway departments were assisted in various lines of their work: Arkansas, Kentucky, Louisiana, North Carolina, Texas, Virginia, and West Virginia.

Reports on county road systems were made for Potter and Wheeler Counties in Texas, and Fresno and Merced Counties in California. Advice was given in regard to special road problems in Alabama, Arizona, Arkansas, California, Louisiana, Minnesota, Oklahoma, South Carolina, South Dakota, Texas, and Wisconsin.

Investigations in regard to bond issues were made to comply with the request of the Capital Issues Committee in Jackson County, Ark., Cook and Madison Counties, Ill., and Oakland County, Mich.

The superintendence of the construction of an experimental post road in Dubuque County, Iowa, was completed.

Engineers were furnished to plan for and superintend the construction of the roads in 16 National Army cantonments; at Quantico, Va., in connection with the Marine Corps, and at Gunpowder, Md., in connection with the establishment of the Edgewood Arsenal for the Bureau of Ordnance of the War Department.

One engineer was assigned to assist the Emergency Fleet Corporation in planning for and building the streets in the villages being constructed by that corporation.

Designs for bridges were prepared as follows: California, 4; Florida, 1; Idaho, 1; Minnesota, 1; North Carolina, 1; South Carolina, 2; Virginia, 2. Engineers were assigned to investigate existing bridges and conditions in relation to proposed bridges in Kentucky and Virginia. General designs and specifications which had been prepared by several State highway departments and local officials were examined and reviewed.

FIELD EXPERIMENTS.

The section of roadway in the Department of Agriculture grounds between Twelfth Street and Thirteenth Street was constructed as a bituminous macadam road, using quartzite as the mineral aggregate. The experimental top-soil road, which was constructed in Prince William County, Va., during the previous year, was maintained, and approximately 30 miles of experimental roads which had been constructed during previous years in Alexandria and Fairfax Counties, Va., and in Montgomery County, Md., were maintained.

ROAD MANAGEMENT AND ECONOMICS.

The economic highway survey, inaugurated toward the end of the preceding fiscal year, was continued. The complete maps and text give detailed information on the roads, bridges, and economic conditions in the territory covered by the surveys. The work has proved of greater value than was at first anticipated, as it brings together in a

workable manner considerable detailed highway information. This work has not only been of value to the State highway departments and this office, but is proving of value to other branches of the Government. Copies of the completed maps are supplied to the Post Office Department, Geological Survey, and the War Department. In certain localities additional data have also been collected and indicated on the maps.

During the year field surveys have been made in cooperation with the State highway departments covering that portion of Maryland east of the meridian, through Washington, or about two-thirds of the entire State; the coastal portion, or 37.4 per cent of the State of New Jersey; the coastal portion or 39.3 per cent of the State of Connecticut; the coastal portion or 65 per cent of the State of Florida; and in addition an area in the vicinity of Camp Lee, near Petersburg, Va.

A set of instructions has been compiled in order that the work of a similar character may be carried out in the various States independent of the assistance from the Government.

ECONOMIC STUDIES OF STATE HIGHWAY SYSTEMS.

In an endeavor to segregate the information which might prove useful in the further development of highway management a very thorough investigation was completed during the year as to the organization, personnel, powers, and duties of State and local highway forces. The study also included the classification of highways and a study of the procedure followed in their construction and maintenance. The method of raising and handling funds for road purposes has been prominently placed in the study.

The results of this study are being published in installments in Public Roads under the caption State Highway Management Control and Procedure.

GENERAL ECONOMIC AND STATISTICAL WORK.

Current data were collected and published in regard to State highway mileage and expenditures and to automobile registrations and the disposition of these revenues. It was found that during the calendar year 1917 the cash expenditures on our rural roads and bridges amounted to a grand total of $279,915,332. Of this total $98,179,332, consisting of $47,290,790 State and $50,888,542 local funds, was expended under the supervision and control of the several State highway departments.

It was also found that a total of 4,983,340 motor cars, including commercial vehicles, and 257,522 motor cycles were registered in the 48 States and the District of Columbia. The sum of $37,501,237 was collected in registration and license fees, including those of chauffeurs, operators, and dealers. Of these fees about 67 per cent, or $23,235,898, was expended more or less directly under the control and supervision of the several State highway departments. As the entire amount of State funds devoted to rural road and bridge work was $47,290,790, those derived from the registration and licensing of motor vehicles, chauffeurs, operators, and dealers formed about 49 per cent of the total.

ADDRESSES, LECTURES, AND PAPERS.

Technical advice has been rendered during the year on legislation, organization, management, construction, and maintenance. This work has been carried on through conferences, lectures, and the presentation of papers. Efforts were made during the year to limit this work to meetings and conferences of official bodies of sufficient State or nation-wide importance to justify the attendance of department representatives. Practically all propaganda work has been discontinued during the period of the war.

A total of 149 lectures was delivered, as compared with 263 during 1917 and 655 in 1916. The total attendance at such meetings was 19,561, as compared with 43,184 in 1917 and 92,610 in 1916.

MODELS AND EXHIBITS.

Practical demonstrations by means of models and other exhibit materials were made during the year to illustrate the various activities of the office. This exhibit material was built and maintained by the office, but all expenses of transportation and installation were paid by the organizations benefited. All exhibit work was carried on in cooperation with the Office of Exhibits of the Department. Exhibits were made at nine places during the year as follows: State Fair, Hutchinson, Kans., September, 1917; International Wheat Show, Wichita, Kans., October 1 to 13; National Farm and Live. Stock Show, New Orleans, La., November 10 to 19; Massachusetts. Institute of Technology, February to October; New York Electrical Exposition, October 10 to 20; Rochester (New York) Industrial Exposition, September; International Exposition, Cleveland, Ohio, September 1 to 9; State Fair, Dallas, Tex., October 13 to 28; Albemarle Highway Association and Chamber of Commerce, Charlottesville, Va., November.

PHOTOGRAPHIC WORK.

The photographic laboratory developed 1,630 negatives, made 6,276 prints, 649 lantern slides, 177 bromide enlargements, and 555 photostat prints. In addition to this work 1,332 lantern slides were colored for lecture work and 5,235 maps were mounted on cloth. For the benefit of various individuals and organizations, including employees of the office, 1,913 lantern slides, 5,203 prints, and 425 bromide enlargements were loaned. At the close of the year the photographic files contained 19,728 negatives, 51,332 prints, and 12,640 lantern. slides.

ROAD MATERIAL TESTS AND RESEARCH.

Research work, as compared with the preceding fiscal year, fell off materially. This was due to loss of employees and inability to replace them with experienced men; also to the fact that cooperation with other branches of the Government in war activities and supervision of material specifications and tests for Federal aid activities consumed much time. Considerable assistance was given to the Fuel Administration in connection with its activities on the United States Highways Council. This work has to do with recommendations relative to granting permits for securing bituminous materials for road

construction and maintenance. Beginning May 13 the Fuel Administration refused to issue permits for the use of such materials in highway work unless applications were first made to the Director of the Office of Public Roads and Rural Engineering and the work approved as an urgent necessity.

The work of the Conference of State Highway Testing Engineers and Chemists, held during the fiscal year 1917, was supplemented by the preparation of two bulletins, both of which have been published. In general, the recommendations of the conference were followed, with a view to standardizing specification requirements of all types of road materials.

Twelve hundred and ninety-eight samples were analyzed in the laboratories during the fiscal year. The decrease of approximately 4 per cent as compared with the preceding year is considered very slight in view of present conditions.

ROUTINE CHEMICAL TESTING AND INSPECTION.

Two hundred and eighty-nine samples were examined in the chemical laboratory. This represents a total decrease of something over 3 per cent as compared with the preceding fiscal year. It is expected, however, that a marked increase will be shown for 1919, owing to check tests which will be made on samples of materials used on Federal aid projects. Of the samples examined 255 were bituminous materials, 12 metal, and 22 sand, soil, and miscellaneous materials.

PHYSICAL TESTS OF ROAD BUILDING MATERIAL.

The physical laboratory tested 1,009 samples, an increase of nearly 10 per cent. as compared with the preceding fiscal year and well above the average annual routine testing. Of these samples, 571 were rock and slag, 117 gravel, 206 sand, clay, soil, etc., 90 cement and concrete, 8 brick, 5 oil, and 12 miscellaneous. Samples were received from all but 12 States of the Union. States from which the largest number of samples were received are as follows:

The results of physical tests of road-building rock in 1916 and 1917 were published as Department Bulletin 670.

MICROSCOPIC EXAMINATION AND CLASSIFICATION OF ROAD-BUILDING ROCK.

The microscopic laboratory examined and classified 630 samples of road-building materials, a decrease of a little less than 7 per cent. as compared with the preceding fiscal year, but well above the average routine work. Of these samples, 322 were rock and slag, and 308 gravel, sand, clay, etc.

RESEARCH ON DUST PREVENTIVES AND ROAD BINDERS.

As a result of research and experimental work as well as observation of the work of highway engineers throughout the country a set of typical specifications for bituminous materials for various types of roads and methods of use was prepared and sent to all manufacturers who were thought to be interested, with the request that they review the specifications and suggest changes if they thought desirable, giving their reasons for such changes. Upon receipt of all the information that could be secured, these specifications were redrafted and published as Department Bulletin 691, under the title, "Typical Specifications for Bituminous Road Materials." This bulletin contains 30 specifications for petroleum, asphalt, and tar products, with descriptions of the general methods of use for which the materials are suitable, methods of testing the materials for conformity with the specifications, and directions for sampling. An investigation of the relation of the consistency of road oils at normal temperature to the so-called asphalt content test has been completed.

The following subjects are under investigation: The effect of variations in refining methods upon the characteristics of road oils and asphalt produced from crude petroleum; the thickness of bituminous films upon different types of mineral aggregates; the physical properties of coarse bituminous aggregates; the effect of colloids on bituminous materials.

EXPERIMENTAL BITUMINOUS ROAD CONSTRUCTION AND MAINTENANCE.

As in 1917, supervision and inspection of experimental bituminous roads has been largely confined to the vicinity of Washington, although inspections of experimental surface treatments of gravel roads were made in Texas and inspections of asphalt earth roads were made in Missouri, Pennsylvania, New Jersey, and Connecticut. In all of the experimental work of the year, which included the maintenance of roads constructed in previous years, this division cooperated with the engineering division. A total of 40 inspections was made.

NONBITUMINOUS ROAD MATERIAL INVESTIGATIONS.

During the year an exhaustive investigation of commercial quarry practice in the production of crushed stone for road-building purposes was begun. A special study was made of such practices in the New England and Middle Atlantic States. A progress report of these investigations was published under the title," The Commercial Sizes of Broken Stone Aggregate," in the June number of Public Roads. A report was also prepared on small scale production of crushed stone for public roads, dealing in an elementary manner with the selection of quarry sites and the installation and operation of suitable equipment. It is felt that such information is of great value in furthering the use of local materials, which is particularly desirable under present war conditions. A paper upon " Saving Fuel in Highway Work" was also published in the May number of Public Roads.